Midterm 1 Flashcards
Interaction of Host and Infectious agent(s); Non-specific Defenses; Acquired Immunity
1
Q
Prions
A
“slow viruses” - protein folding problem. Spongiform encephalitis.
Kuru,Creutzfeldt-Jakob, scrapie in sheep, bovine spongiform encephalopathy (BSE) in
cattle.
single proteins but have the capacity to wreck havoc on brain cells of an individual. Prions have many similarities with viruses which is what confuses people.
Prions are pathogens discovered by Stanley Prusiner. These are infectious agents that cause many neurodegenerative diseases such as transmissible spongiform encephalopathy. Surprisingly, prions are made up of harmless proteins that are found in mammals and birds. But these proteins are in abnormal form and once they enter human brain, they are capable of severe brain infections. Normally these prions are ingested but they also get formed through mutation of a gene that contains this protein. One thing that seperates them from viruses is that they lack nucleic acids (RNA and DNA).
As soon as prions find their way into brain, they cause normal proteins to turn into abnormal ones. They soon multiply causing severe infection. Holes appear inside the brain that can only be treated by incineration.
2
Q
Viruses
A
genetic material (RNA or DNA, never both), protein, lipid.
Commandeer host metabolic machinery to replicate.
Polio, small pox, chicken pox, herpes, AIDS
(HIV), measles.
Viruses are made up of proteins and nucleic acid and lipids. These nucleic acids (RNA and DNA) contain the genetic code that helps these viruses to grow and reproduce once they find their way into a living organism. The nucleic acid remains covered in a protective covering called capsid. Before invading a living thing, viruses are in extracellular form and are known as virions. These virons, once they find a host cell transform into an intracellular form when the capsid gets removed and only nucleic acid remains. Viruses take help of the building materials of the host to grow and reproduce.
3
Q
Bacteria -prokarotes (before nucleus) -
A
lack internal organelles. Single cells.
About 30 genera cause disease. Strep., Staph, TB, gonorrhea, RMSF, etc.
4
Q
Eukaryotes (true nucleus)
Fungi
A
- saprophytes - single cell or multicellular or one to the other: yeast to
mycelial phases. Athlete’s foot, “yeast” infections. Not all bad, some make beer
and wine!
5
Q
Eukaryotes (true nucleus):
Animals
A
protozoa - single cell animals. Malaria, Montezuma’s revenge,
Giardia.
- Multicellular - flat worms (tapeworm); round worms (schistosomiasis).
6
Q
Study of the Host (Us) responses to infection:
Non-specific:
A
tears, skin, flow of liquids out, phagocytes
7
Q
Study of the Host (Us) responses to infection:
Specific:
A
Immunity = Immunology
Humoral (blood) = antibody; protein molecules that bind to foreign material
and inactivate it.
Cellular (cell-mediated immunity) = cells interact with foreign material to
kill also control immune response. CD4+, CD8+, etc.
8
Q
Humoral (blood) =
A
antibody; protein molecules that bind to foreign material
and inactivate it.
9
Q
Cellular (cell-mediated immunity)
A
cells interact with foreign material to
kill also control immune response. CD4+, CD8+, etc.
10
Q
History of Medical Micro
longterm or short term & eg
A
is very long from organism’s point of view. “Germs”
(Hollywood term) have been around for millennia.
Bacteria - Tuberculosis in 5,000 yr old mummies. TB, a disease of the lung, is also
known as consumption, the white plague, or wasting disease.
Many diseases described by the ancients are hard to nail down. e.g. leprosy (Bible)
was probably a fungal disease, not leprosy. Others are dead certain.
11
Q
Black Plague:
A
Yersinea pestis.
The great black death. Bubonic and pneumonic
plague. Changed history. The first pandemic occurred in 500 AD, altered the
Roman Empire. The 2nd pandemic occurred in 1250 - 1350 AD. Knocked Europe
out of the dark ages. 25% of the population killed.
12
Q
Bubonic plague -
A
spread by bite of rat flea. Swollen lymph nodes, black (buboes).
Spreads to entire body, especially lungs, leading to a characteristic wheezing
snuffle. Ugly red/black spots occur on the skin as blood leaks into skin. The victim
becomes very morose and turns blue/black from lack of oxygen, becomes prostrate,
70% die within 7 days.
13
Q
Pneumonic plague -
A
spread by aerosol droplets from patient with lung infection.
Droplets are inhaled, they infect lung. Ninety percent of the people with pneumonic
plague die within 24 hours. Physicians came to treat and clergy came to give last
rites - they died from pneumonic plague before the patient did. Wiped out the
educated classes and resulted in physicians refusing to make house calls (ha, ha!).
14
Q
brought small pox to he New World
A
1500 - Cortez brought small pox to he New World. The first Indian epidemic
occurred in 1520, reaching the Rio Grande in 1527. Estimates of Aztec deaths range udd, RC, El Med Micro, page 3
from 20-50% of the population. The Indian population had never seen this disease
(no premunition). The officers Amherst and Bouquet were the first to use small pox
as a biological warfare agent during the French/Indian wars (circa 1760). It appears
that the US government used small pox to subdue native Americans in the 1800s.
15
Q
1650 - Antonie van Leeuewenhock invented
A
1650 - Antonie van Leeuewenhock invented compound microscope and saw
“animicules”.
16
Q
1798 - Edward Jenner
A
1798 - True Vaccination.xxxxx described immunization with cow pox
(vaccinia) to prevent small pox (variola).
17
Q
1854 Snow
A
1854 - Contagion - Snow recognized cholera was spread from the Broad Street
pump in England
18
Q
Robert Koch and Louis Pasteur
A
Two rivals, much as Germany and France. Both
National Heros. Pasteur was flamboyant, lots of press, serendipity. Koch Teutonic,
meticulous.
19
Q
Koch -
A
Koch - pure culture technique, solid media. First used potato slices to grow TB,
then gelatin, but too many bacteria liquify gelatin so he used an extract of the sea
weed Agar agar, to solidify media. He developed staining techniques and studied
TB, anthrax and cholera, to name but a few of his accomplishments.
20
Q
Pasteur -
A
Pasteur - “Father of Microbiology” - developed attenuated vaccines for anthrax and
chicken cholera. He produced the first viral vaccine for rabies (saved boy, became
guard for Pasteur Institute in Paris - killed in line of duty). Amazing dude.
21
Q
Hx
A
1890’s - Eli Metchnicoff - Russian who developed cellular immunity studies
Thanatology.
1900 - Bacillus Calmette-Guérin - TB vaccine.
1904 - Plague spreading worldwide.
1930s - Vaccines for tetanus, diphtheria.
1943 - Chain and Fleming - penicillin - antibiotic age began.
1950s - Salk polio vaccine, then Sabin.
1960s -70s - viral vaccines - measles, mumps, etc.
1980s - Microbiological Revolution: Immunology, recombinant DNA
technology (molecular biology). AIDS
1990s - Chicken pox vaccine. Cancer (genes), transgenic mice, gene therapy,
transplantation, new drugs (AZT, ddl, protease inhibitors), new antibiotics, etc.
Absolute explosion of knowledge. Decade of STDs. Use of bacterial or fungal
products e.g. streptokinase, coagulase, Protein A and G (even shark immune
molecule to fight cancer). Cloned products: Factor 5 - hemophiliacs; Interferon
- anti-cancer; Insulin; vitamins; Cyclosporin - fungal transplantation drug.
2000- Era of genetic miracles. Gardasil - HPV vaccine
22
Q
Extremely relevant today:
A
Extremely relevant today: Most common infectious disease? Dental caries; Judd, RC, El Med Micro, page 4
athlete’s foot; ascariasis. Most common life threatening? Tuberculosis and malaria.
Second most common? Schistosomiasis.
23
Q
Current disease problems:
A
Staphylococcus aureus - first completely drug resistant bacteria.
Escherichia coli 0157:H7 - enterohemorrhagic diarrhea.
Streptococcus pyogenes - “flesh-eating” bacterium.
Bordetella pertussis - whooping cough. Recent outbreaks in Idaho, MT.
Salmonella typhimurium - milk-born outbreaks in Illinois, Wisconsin and
Minnesota. Associated with fowl.
Giardia lamblia - giardiasis - western MT streams.
Brucella abortis - disease in bison leaving in Yellowstone Park.
Mycobacterium tuberculosis (and related species) - tuberculosis - AIDS
epidemic has spawned a TB epidemic.
Vibrio cholerae - cholera - Rwanda, Peru, Brazil, India.
Pasteurella pestis - plague - India. Potential bio-terror agent.
Borrelia burgdorferi - Lyme Disease.
Bacillus anthracis - zoonose and a bio-terror agent.
Sinomber virus - “hanta-like virus” - respiratory disease.
Human immunodeficiency virus - AIDS.
Ebola virus
Encephalitis viruses
Bovine spongiform encephalopathy (BSE) - prion. Mad cow disease.
Norwalk-like viruses; Rotaviruses
Severe Acute Respiratory Syndrome (SARS)
Asian bird influenza
Human papilloma virus (HPV); a new vaccine - Gardasil.
Influenza HIN 1
24
Q
Infection v disease
A
Infection is not necessarily disease; disease is damage to the host mediated by the
infectious agent; pathology is the disease (i.e. damage) caused by the infectious
agent; virulence is a quantitative measure of the ability of an infectious agent to
cause disease. Pathogenic - potentially disease-causing.
Disease can be due to a toxin (poison); damage to cells or host tissues; nutrient
depravation, blockage of vessels etc.
25
Prions; Viruses; Prokaryotes (bacteria); Eukaryotes
protists - single cell;
multicellular. Among the Eukaryotes are fungi and animals. Plants generally are not
infectious agents.
26
Carbon, nitrogen, oxygen, phosphorous, hydrogen,
sulfur. Trace elements are also required such as iron, zinc, calcium, etc.
Carbon, nitrogen, oxygen, phosphorous, hydrogen,
sulfur. Trace elements are also required such as iron, zinc, calcium, etc.
27
Molecules of life:
nucleic acids:
```
ribonucleic acid (RNA) and deoxyribonucleic acid(DNA) - adenine,
guanine, cytosine, thymidine, and uracil (replaces adenine in RNA) + ribose (RNA)
or deoxyribose (DNA); genetic material and involved in translating the genetic code
into protein.
```
28
Molecules of life:
proteins -
- strings of amino acids (22) peptide bonds; primary structure - the amino
acid sequence; secondary structure - the interaction of the amino acids in the string;
tertiary structure - the important stuff, the folding of the protein to assume its
functional structure - temperature, acid/base, electrolytes and other
considerations can effect tertiary structure; quaternary structure - interaction of
two or more proteins to form a functional structure (insulin A and B chains).
Structural, enzymes, toxins, antibodies, hormones.
29
Molecules of life:
carbohydrates -
sugars - hydrogen and oxygen in the same ratio as water. Structural,
energy conversion.
30
Molecules of life:
lipids - fats
long chains for carbon. If double bonded = unsaturated; single bonds
= saturated. Glycolipids, fatty acids, sterols. Membranes, structural, hormones,
energy.
Glycoproteins, lipoproteins (proteolipids), etc.
31
Infectious Agents:
Prions; Viroids
Viruses
Bacteria (prokaryotes)
Eukaryotes: fungi, protista, animal
32
viruses
Viruses: are they alive? Philosophical question.
Life is often defined as: 1) the ability to metabolize (grow); 2) reproduce; 3)
respond to the environment. Viruses can't really do any of these independently.
Therefore, viruses are not "organisms" whereas bacteria and eukaryotes are. I refer
to viruses as infectious agents. Viruses cause many common diseases such as head
colds, influenza, intestinal diseases, etc.
Viruses range in size from 0.02p.m diameter, averaging 0.1 |im. They lack sufficient
metabolic machinery to replicate and grow. Virus enters host cell, releasing its
nucleic acid, some "early" enzymes such as polymerases, then shuts down host
replication and forces the host cell to produce proteins directed by the virus. Some
viruses integrate their nucleic acid into the hosts genome and can be passes from
parent to offspring. "Late" proteins are produced involved in the structure of the
virus and packaging of the replicated viral nucleic acids into the viral "head". Virus
either ruptures cell or buds out. It may pick up some host membrane that acts as a
envelope.
Basic Viral Structure: See "Introduction to Viruses notes" notes, page 46.
RNA vs DNA; single strand vs double strand; + strand vs - strand. Capsid.
33
Bacteria (prokaryotes)
Bacteria are small (l-40p,m in diameter, averaging 5p.m),
single cell organisms generally capable of free living. Most bacteria are good.
Involved in remineralization, food (cheese, yogurt, sour cream, black tea, coffee,
etc.). Only about 30 genera cause disease and only a few are dependent on humans.
Most are accidental infections. Unbelievable distribution in nature, living with air
(aerobic), without air (anaerobic). Some metabolize sulfur, producing sulfuric acid,
others live at 70°C. Others live in up to 20% salt - that would pickle you! Some'
photosynthesize others live deep in frozen glaciers in Antarctica
Circular chromosome of DNA; transcribe mRNA; translate to protein. Many have plasmids - self replicating genetic elements. Most have restriction/modification systems. Some can resist drying (endospores). They multiply by binary fission.
34
Classification of bacteria
a nomenclature vs a taxonomy, e.g. bacteria can't be distinguished
based on structure. Biochemical distinctions. Enzymes, genetic content. Five major
structural types: coccus, bacillus, vibrio, spirochete, pleomorphic. Two major
groupings: Gram +; Gram -. see "Bacterial Disease", page 63 . Other stains, acid
fast, silver, etc.
Some have capsules of protein or carbohydrate (meningococcus; pneumococcus),
some have flagella - motility; Fimbria/pili - adherence, sex.
Basic Bacterial Structure: see "Bacterial Diseases" page 63.
Gram +; Gram -; various shapes; LPS; cell walls; toxins; spores
35
5 major structural types of bacteria
coccus, bacillus, vibrio, spirochete, pleomorphicf
36
Eukaryotes:
Fungi: asexual (budding) reproduction - ascospores; conidiospores; arthrospores
or by sexual reproduction.
Zygomycetes, ascomycetes, basidiomycetes, deuteromyctes
Yeast vs mycelial
Protista: Single cell organisms of plant, animal, fungi and algae
Animal: Malaria; giardia; Entamoeba; Leishmania; etc. Multiply by sexual
reproduction.
37
relationships between infectious agents and humans
1. Couldn't care less - Free living. Most organisms by far.
2. Commensal - "sharing a table". No damage.
3. Symbiotic (mutualism) - both gain...Normal flora.
4. Parasitic - it harms you.
May or may not cause disease. For disease there must be a PATHOLOGICAL
CHANGE in the host.
5. Saprophytic - live on dead and decaying material.
38
Factors of organisms that influence disease
For infectious agents to succeed they must:
1. Get from host to host - TRANSMISSION.
2. Correct portal of entry.
3. Find correct "niche"
39
Get from host to host - TRANSMISSION. We are mortal so bugs must get from
you to me to someone else. Examples are NOT COMPLETE.
DIRECT CONTACT - Staph, herpes, athlete's foot
SEXUAL or VENEREAL transmission - HIV, HPV, gonorrhea,
chlamydia, syphilis
RESPIRATORY - Strep, influenza
FECAL/ORAL - salmonella, giardia, cholera, polio
WATER; FOOD
FOOD - botulism, salmonella, various food infectious agents
FOMITE - inanimate objects (drinking fountain, forks, etc.) - some of the
above
VECTORS - living agents that transmit disease. Black plague, Rocky MT
spotted fever
Horizontal transmission - among a population.
Vertical transmission - parent to offspring.
40
2. Correct portal of entry
Mouth, nose, cut, ear, etc
41
3. Find correct "niche"
0 2- aerobic, anaerobic. Gangrene, tetanus vs strep.
Correct pH - acid/base. Stomach low (pH 2) gut high (pH 9). Tissue pH 7.4.
Correct nutrients.
Overcome other organisms (e.g. normal flora). Tetracycline/yogurt.
Overcome host defenses.
42
Do infectious agents live extra or intra cellularly?
Most bacteria, fungi and some parasites live extracellularly. Some live
intracellularly (TB, Chlamydia, malaria). All viruses are obligate intracellular
infectious agents. Some organisms can live in or out of cells
43
PATHOGEN
potentially disease-causing
44
VIRULENCE
quantitative measure
of disease.
45
Infection vs disease, e.g. Normal flora vs a pathology
Infection is the process of gaining entry and growing. Disease is a detrimental
change in host tissues or structures caused by the infecting agent. That detrimental
change is called PATHOLOGY.
We contact pathogenic (potentially disease-causing) agents all the time!
46
what are the 4 outcomes when We contact pathogenic (potentially disease-causing) agents?
1. Most common - we control and destroy with no symptoms. Our Immune
Systems protect us.
2. We get sick and then recover, destroying the agent.
3. We control it but we become carriers - Typhoid Mary.
4. It kills us.
47
Exogenous v Endogenous
from without
from within
48
Types of INFECTIONS:
Local - remains at one site. A zit.
Focal - spreads to other sites from a point source. Tetanus.
Systemic - throughout body. Plague.
Primary - disease results from invading agent.
Secondary - disease caused by other agent(s) as a result of debility due to
disease or therapy. Cortisone, chemotherapy, AIDS.
Mixed - two or more agents involved. Staph/strep + tetanus.
Inapparent or subclinical - most common. You have an immune response but
never any symptoms.
49
Local infection
Local - remains at one site. A zit.
50
Focal infection
Focal - spreads to other sites from a point source. Tetanus.
51
Systemic infection
throughout body. Plague.
52
Primary v secondary infection
Primary - disease results from invading agent.
Secondary - disease caused by other agent(s) as a result of debility due to
disease or therapy. Cortisone, chemotherapy, AIDS.
53
Mixed infection-
two or more agents involved. Staph/strep + tetanus.
54
Inapparent or subclinical -
You have an immune response but
never any symptoms.
55
-EMIAS
what are they?
examples?
- "bugs" in the blood.
## Footnote
BACTEREMIA - transitory state where bacteria are in the blood moving to another spot.
SEPTICEMIA - blood is the infected tissue.
PYEMIA - pyogenic bacteria in blood (staph/strep).
TOXEMIA - poison in blood. Tetanus, etc.
VIREM1A - virus in blood.
PARASITEMIA - parasite in blood. Malaria.
56
Whether a pathogen causes disease depends on the relationship between the agent and the host. Very complex.
Factors of the agent:
* **Ability to invad**e - enzymes (hyaluronidase, proteases, lipases, neuraminidase, nucleases).
* **Capsules** - polysaccharide or protein. Antiphagocytic.
* **Toxins** - poisons.
* **-Exotoxins** - usually poisonous proteins (tetanus, botulism, diphtheria). Exotoxins are often described by the organ or tissue affected: e.g. enterotoxin -gut poison; neurotoxin - brain of CNS toxin, etc.
* **-Endotoxin** - lipopolysaccharide (LPS) of Gram negative bacteria. Fever, shock, intravascular coagulation.
* **Motility** - flagella, cilia.
* **Adherence** - fimbria(ae)/pilus(i), receptors on viruses and parasites, etc.
* **Antigenic variation** - ability to change surface at high rate, confusing our IR
57
Whether a pathogen causes disease depends on the relationship between the agent and the host. Very complex.
Factors of the Host that affect our resistance to disease:
* **Premunition** - physiological ability to resist infection due to generations of contact.
* **Age** - very young (immature immune system); very old (deteriorating immune system).
* **Genetic ability to resist diseases** - Correct immune response genes (strepsusceptible).
* **Nutrition**.
* **Occupation** - Health care workers (HIV, hepatitis, etc.). Ranchers (brucella, leptospirosis). Abattoir workers, prostitutes, etc.
* **Other diseases** - diabetes, cancer, infectious diseases.
58
Non-specific Resistance
The "First Line of Defense":
Physical/Chemical Barriers
59
Physical/Chemical Barriers
Portals of entry
* Skin surface - integument, Largest organ of body. Fatty acids, salinity, pH 5, normal flora. Abrasion, cuts, bites (insects/rabies).
* Mucous Membranes - all the orifices of our body are lined with mucous - viscous fluid, sticky with neuraminic acid.
* Ears - ear wax.
* Nasopharynx - mucous, expectoration, nose hair, flow out, etc.
* Oropharynx - mucous, expectoration, lysozyme, lytic enzymes.
* Respiratory tract - many get in few cause disease. Mucous, cilia, flow out.
* Eye - mucous, tears, lysozyme.
* Gut - low stomach pH (Helicobacter), intestine high pH. Lytic enzymes, bile salts, peristalsis normal flora.
* Urogenital tract - flushing with urine, flow out, low pH of vagina (pH 4-5), normal flora (pill).
60
Physical/Chemical Barriers
Chemicals:
Acid, bases, bile salts, enzymes (lysozyme, proteases, lipases, nucleases, etc.).
Acid: a low "pH" - meaning lots of free H+ ions around; Base: a high pH -meaning lots of OH- ions around.
pH 7.0 means there is an equal number of H+ ions and OH- ions (neutral). Most of our tissues are about pH 7.4 (very, very slightly basic).
61
The "First Line of Defense": Physical/Chemical Barriers
Mechanical Flow
flow of tears, saliva, urine, blood is all OUT! Washes organisms away
62
The "First Line of Defense": Physical/Chemical Barriers
Normal Flora:
Organisms that live with us. Cover up sites, produce antimicrobial agents, etc
63
The "Second Line of Defense":
```
Elements of the blood and lymph,
Reticuloendothelial System (RES), a system of phagocytes and inflammation.
```
64
Blood:
plasma
serum
Blood - great stuff. Its an organ. -50% cells, - 5 0 fluid
Fluid portion of blood is called plasma. If the clotting factors have been removed,
serum.
Plasma exits blood to bathe tissues with 0 2
and nutrients. If too much, swelling
(edema). Fluid is returned to blood by lymphatic system.
Plasma has lots of good stuff in it. Toxic peptides (short proteins), complement,
antibody, interferon, etc.
65
Cells in the blood - all are derived from?
derived from "stem cell" which is produced in bone
marrow (hematopoietic system):
66
Erythrocytes (red blood cells - RBCs)
do what?
Transport 0 2
(hemoglobin).
67
White blood cells - Two types:
**Granulocytes** (they have granules in the cytoplasm)
**Agraulocytes** - no granules. "CBC" "WBC" or Differential bloodcount.
68
Granulocytes - Three cell types named based on staining in haematoxylon, eosin stain.
* **Eosinophiles** - Granules stain red with acid eosin. Involved in down-regulating inflammation, allergic reactions and controlling parasitic diseases.
* **Basophils** - granules stain purple with basic dye. Granules are mainly HISTAMINE, the stuff of inflammation. Up-regulate inflammation. Some become bound, or "fixed" in the endothelium and are called MAST CELLS.
* **Neutrophils (polymorphonuclear cells -** PMNs, polys, "white cells" or Microphage) - most abundant WBC granules stain pink (neutral dye). Granules are lytic enzymes, alkaline phosphatase, and such. Phagocytic cells - the ingest and degrade foreign material. They can exit the blood in hot pursuit of bad stuff.
69
**Agraunulocytes** - four cell types. Cells lack cytoplasmic granules.
* **Monocytes** - large phagocytic cells. The blood form of a large group of phagocytic cells called macrophage. The can enter and leave blood. They are involved in initiating the immune response and are critical elements in destruction of foreign material. We'll talk more about macrophage later.
* **Lymphocytes** - cells that mediate the specific immune response. Much more later.
* **Platelets** - very small cells involved in blood clotting.
* **Natural killer cells** - subset of lymphocytes that can directly kill foreign cells. Receptors for bacterial and viral "motifs" (toll-like receptors).
70
Lymphatic system
a passive circulatory system that returns plasma (lymph) to the
blood.
71
Reticuloendothelial System (RES)
- a system of fixed and circulating phagocytes
(macrophage) . Fixed in lymph nodes, spleen and liver.
72
Phagocytosis
"eating cell". The process of ingesting and killing foreign material.
73
chemotaxis
"chemical attraction". Cells moving up a concentration gradient.
74
Oxidative killing:
Increase in metabolism leads to 02 being converted to 02 - (superoxide) which spontaneously generates H2 0 2
H202 + CI- (myeloperoxidase) = HOCl (hyperchlorite). Oxidizes the bejesous out of bugs.
75
Inflammation
response to tissue damage. Short term (acute) good. Long term
(chronic) bad.
76
Class I histocompatibilty molecules vs Class II
Class I
* molecules expressed on the surface of virtually all nucleated cells
* Deficiency can present clinically as a profound CD8 T cell deficiency.
Class II
* molecules found on antigen-presenting cells (macrophage dendritic cells) and some lymphocytes.
* Deficiency can present as chronic infections, low Ig in serum, bone marrow transplant indicated.
77
What do mast cells do when tissue is damaged?
When tissue is damaged, MAST CELLS release HISTAMINE
78
HISTAMINE:
what does it do?
- chemotactic for PMNs (polymorphonuclear cells) and Macrophage
- increases vascular permeability (vessels leak) - bringing plasma stuff to site
- increases vascular dilation - brings "core" blood to site
- constricts smooth muscles - compresses area to restrict motion of bad guys,
- causes pain (bradykinin)
79
Four Cardinal Signs of Inflammation:
* Heat - Calor - increased blood flow
* Pain - Dolor - pressure of plasma and cells, histamine causes pain
* Swelling - Turgor - volume of plasma, swollen vessels and cells
* Redness - Rubor - increased blood flow
* Sometimes loss of function - Buggor (ha, ha).
80
Immunity
state of resistance to foreign material characterized by specificity and memory (anamnestic ["not forgetting'] response). Mediated by lymphocytes. When an immune response is mounted, lymphocytes proliferate (divide) and differentiate (specialize).
81
B-lymphocytes
are found fixed (unable to move) in the spleen, liver and
lymph nodes
bone marrow-derived lymphocyte, matured in the Peyer's
Patches of the pancreas, having antibody of a predetermined specificity on its
surface. If activated by antigen the B-cell excretes antibody of the predetermined
specificity.
82
T-lymphocytes
* are found fixed in the spleen, liver and lymph nodes as well as found circulating in the blood and tissues.
* lymphocyte which **matured in the thymus gland**, **having receptors of a predetermined specificity,** responsible for cellular immunity and regulation of the immune response. **Comprises -75% of the circulating lymphocytes.**
* Two major groups:
* **helper/DTH - CD4+**
* upregulate the immune syst
* **suppressor/cytotoxic - CD8+**
* down regulate the immune system
83
Cell-mediated immunity
- specific immune response mediated by T-cells, which
produce lymphokineSj, such as interleukin-2 (IL-2) through IL-n; chemotaxins
(molecules"that attract other cells); tumor necrosis factor; interferons; etc.
84
Humoral immunity
blood immunity. Specific immunity mediated by antibodies -
large glycoproteins, produced and released by B-cells, which bind specifically to
antigen.
can't go in brain- blood brain barrier
85
Macrophage ("large-eaters")
- these cells play an essential role in processing and
delivering **immunogens** to lymphocytes (**Afferent Branch**) and are important
effector cells (cells that carry out destruction of foreign material) under the influence
of T-lymphocytes (**Efferent Branch**). They also carry receptors for antibody,
allowingthem to "grab" foreign material. Macrophage are called monocytes if found
in the blood.
86
Active Immunity
specific immune response mounted by the host in response to
infection or vaccination,
87
Passive Immunity
transfer of preformed antibodies to a non-immune individual by
means of blood, serum components, etc. (e.g. maternal antibodies transferred via
breast milk or placenta) or the inj ection of antibodies to prevent or modify infections
(e.g. tetanus antitoxin)
88
Immunogen
***any molecule which stimulates an immune response.*** Good immunogens are large, complex, rigid, and must be identified as foreign. Other
factors influencing our ability to respond to an immunogen include **epitope density**
i.e. the number of sites [called epitopes] our immune system can respond to on a
molecule) and our genetic ability to respond to the particular immunogen.
In general, proteins are the best immunogens, followed by carbohydrates, then
nucleic acids. Lipids tend to be very poor immunogens.
89
antigen
any molecule which reacts with an immune response. A molecule can
have many different epitopes
'Antigen" is often used to refer to both the Immunogen and Antigen since they
are often the same molecule.
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Afferent branch
all those reactions which lead up to an immune response. This includes ingestion, degradation and delivery of immunogens by macrophage to the appropriate **B-cells** and **T-cells** (lymphocytes which have preformed receptors for a specific immunodeterminant site), **differentiation** and proliferation of the B- and T-cells and generation of the appropriate regulatory molecules (**lymphokines**) by T-cells and synthesis of antibodies by B-cells. This process takes **4-7 day**s. Once complete, the afferent response has led to sensitization of the T-cells and B-cells to the specific immunogen. **Sensitized** = **immunocommitted** = primed. B-cells can react directly with the immunogen
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Efferent Branch
all the reactions which result from the immune response
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There are two branches of the immune response:
afferent branch
efferent branch
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There are three types of effector immune responses:
1. **Humoral (blood)** - antibody production by B-cells under the control of T cells
2. **Cell-mediated or Cellular** - delayed-type hypersensitivity and Cytotoxicity mediated by **CD4+ **and **CD8+ T-cells**, respectively
3. **Tolerance** - a specific non-response under the control of **T-cells**. We are tolerant, or specifically non-responsive, to our own tissues.
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Antibodies, large glycoproteins, protect us in five important ways:
1. **Neutralization** - antibody binding covers toxic sites or receptor sites on molecule or virus.
2. **Opsonization** (antibody-enhanced phagocytosis) - macrophage have receptors on their surface which bind to antibody, allowing them to "grab" the foreign material.
3. **Complement fixation -** complement is a series of 11 serum proteins. When certain antibodies bind to foreign material, the first complement component is activated, which then activates the next component, and so on until all 11 proteins are activated. This accomplishes several important functions such as amplifying the immune reaction, attracting macrophage and disrupting the membranes of cells.
4. **Agglutination/precipitation** - antibody cross-links cells (agglutination) or molecules (precipitation) to form large, easily phagocytized aggregates.
5. **Immobilization** - antibody binding to motility structures on bacteria disrupts their function, making it easier for macrophage to ingest the bacteria.
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There are five classes of antibody based on the amino acid composition of their heavy chains:
* **IgM -** largest antibody having a **pentamenric** structure. Found in a monomeric form on the surface of mature B-cells. Produced first in the immune response. **Able to neutralize, fix complement, agglutinate/precipitate, and immobilize antigens**
* **IgG** - main **serum antibody** having a monomeric structure. Synthesized as part of the secondary immune response. Able to neutralize, opsonize, fix complement, agglutinate/precipitated, and immobilize antigens.
* **IgA** - antibody found on **mucosal surfaces** (secretory antibody) having a monomeric, dimeric, or trimeric structure.
* **IgD -** receptor antibody found on the surface of immunocompetent B-cells. Monomeric structure. Functions only in the Afferent Branch of the immune response.
* **IgE** - **reaginic** antibody. Binds to the surface of mast cells through its Fc piece (constant region). When antigen binds to IgE, the mast cell degranulates, dumping histamine resulting in "allergies" (hay fever, hives, anaphylactic shock. Very low concen
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Complement
is a series of 11 serum proteins which are activated in a cascade (i.e. the first component acts on the second component which in turn acts on the third component and so on). Complement can be activate in two ways: antibody activation results when IgG or IgM bind to an antigen; alternate pathway activation occurs when complement component C3b binds to complex
polysaccharide (e.g. lipopolysaccharide). Complement activation results in: amplification of the response; chemotaxis; immune adherence; cellular lysis.
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Cellular Immunity is often directed against
intracellular parasites (e.g. viruses,
tuberculosis, etc.) and cancer. Infected cells and the pathogen are killed by
macrophage under the direction of CD4+
T-cells. Cytotoxic T-ceIls(CD8+) interact
directly with the infected or foreign cell, releasing toxins and lysins (perforins, granzymes) which kill the cell.
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the main types of immunity in man
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Major Histocompatibility Complex (MHC)
The MHC is a genetic region where
genes involved in the immune response are located. These include genes for
antibodies, T-cell receptors, genes that modulate the immune response (e.g.
interleukins, lymphokines, etc.) and histocompatibility antigens. These are
molecules on the surface of our cells that help identify the cells as belonging to us.
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Immunogen vs. Antigen
**Immunogen** - Agent capable of binding immune
receptors AND inducing an immune response by B
cells or T cells
**Antigen** - Agent that binds with varying degrees of
specificity to immune receptors (antibodies on B cells; T
cell receptor on T cells)
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How does sensitization occur?
Macrophage process and deliver antigens to lymphocytes. For sensitization to occur,
the macrophage must also deliver Class I or Class II MHC antigen. If Class I antigen plus the foreign antigen is delivered, CD8+ T-cells (cytotoxic) are stimulated. If Class II antigen plus the foreign antigen are delivered, CD4+
T-cells are stimulated. The CD4+
subset is divided into two groups, the T-helper 1 (Th 1), which regulate other T-cells and are involved in delayed-type hypersensitivity, and Th2, which regulate B-cells
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Hypersensitivity occurs when...
when the immune response, as part of its normal operation, damages normal healthy tissue. There are Immediatxe hypersensitivities (damage occurs in minutes) which are mediated by antibodies
and Delayed hypersensitivity mediated by CD4+
T-cells.
Hypersensitivity = allergy
There are four categories
of hypersensitivity:
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There are four categories
of hypersensitivity:
Type I- Anaphalactic
Type 2- Cytolytic
Type 3- Immune Complex Disease
Type 4- Delayed-type Hypersensitivity
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Type 1 - Anaphylactic
("not protective"): results from the binding of antigen to IgE bound to mast cells. Degranulation of mast cells causes the release of histamine
causes smooth muscle contraction, capillary dilation, increased vascular permeability
and attracts macrophage and lymphocytes. **Hay fever, hives, and food allergies**.
Massive release of histamine is fatal in 5 minutes (e.g. bee sting deaths).
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Type 2 - Cytolytic:
Activation of complement by IgG or IgM results in damage to bystander tissue. Alteration of normal tissue can also result in cytolytic
hypersensitivity (e.g. penicillin binds to red blood cell surface, antibody to penicillin
binds and lyses RBC).
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Type 3 - Immune Complex Disease:
Massive precipitation or agglutination of
antigens by IgG or IgM results in "immune complexes" being deposited in the
tissues. Complement is activated and bystander tissue is damaged. Examples include
rheumatoid arthritis, serum sickness, and glomerular nephritis.
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Type 4 - Delayed-type Hypersensitivity:
CD4+ T-cells contact their antigen in
tissue and release lymphokines which attract macrophage, hold the macrophage at
the site, stimulate the macrophage to engulf and digest material and divide. More Tcells are also attracted and turned on, compounding the reaction. Tissue is damaged
by the activate macrophage. It takes 24 to 48 hours to mount the reaction, thus "delayed".
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Autoimmunity occurs when...
the immune response is mounted against your own
tissue. This results from: exposure of sequestered antigens (e.g. lens of eye, brain, testes); arisal of a "forbidden clone" where tolerant cells are inappropriately activated; neoantigens result from some disease processes and therapies. Normal
tissue thus looks foreign and stimulates an immune response; cross-reaction with bacterial of viral antigens (e.g. Streptococcal infections).
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Bacteria are...
single cell organisms know as prokaryotes (before nuclei). They lack internal organelles (membrane-bound internal components). Organisms with internal
organelles are called eukaryotes (true nuclei).
They have RNA, DNA, proteins, lipids, carbohydrates, etc. They are capable of free living (growth, reproduction and reaction to the environment), multiplying by binary fission.
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van Leeuwenhoek
bacteria first observed by
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Robert Kock
first demonstrated how
to isolate bacteria in pure culture and developed the first staining techniques
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Gram
developed a stain that separated most bacteria into two groups: Gram positive (retained the primary dye) and Gram negative (did not retain the primary dye).
Bacteria are very small (~1 - ~40(im). The two basic types (Gram+ and Gram-) have different structure, see "Bacterial Diseases" page 63.
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Gra Pos vs Gram Neg
Gram positive have a single cell membrane, thick cell wall and teichoic acids. Gram negative have an inner and outer membrane, a thin cell wall and lipopolysaccharide (LPS). Because LPS is a constitutive component of the bacterium which is only released when the organism dies, and is poisonous (toxic)in humans, it sometimes called endotoxin. Toxins that are released by living bacteria are called exotoxins.
Both types may have a capsule (usually carbohydrate and often antiphagocytic), pilus(-i) (involved in genetic transfer), fimbria(-)e (adherence structures)[often called pili as well] or a flagellum(-a). They come in several basic shapes: spherical -
coccus(-i), rod shaped - bacillus(-i), comma shaped (vibrio), and thin corkscrews (spirochete). Pleomorphic bacteria can assume many shapes. Loose spirals are called spiral bacteria! See "Bacterial Disease" page 63.
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Bacteria are sometimes named based on their characteristic shapes:
: diplococci (two
cocci); staphylococci (grape spheres); streptococci (chain spheres); streptobacilli
(chain rods).
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Are bacteria non-pathogenic?
Almost all bacteria are non-pathogenic. Only thirty, of the several thousand genera, contain pathogens. Most pathogenic bacteria only accidently infect man. Most
bacteria are free-living, being responsible for remineralization (returning carbon, nitrogen, phosphorus, etc., to elemental form for reuse by living organisms). They live in a huge variety of environments. Some eat gasoline, crude oils or plastic.
Others produce sulfuric acid. Some are photosynthetic.
Very few bacteria species are obligate human pathogens.
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4 types of bacteria names based on oxygen
Aerobic bacteria require oxygen.
Anaerobic bacteria are killed by oxygen.
Microaerophilic bacteria grow with very little oxygen.
Facultative bacteria grow with or without oxygen.
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Endospores
Some bacteria produce durable, resistant bodies known as endospores that allow the
organism to survive drying, heat, etc. The two major genera that form endospores
are: Bacillus spp. (aerobic, Gram+ soil bacteria) and Clostridium spp. (anaerobic,
Gram+ soil bacteria).
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immunocommitted/primed/sensitized
Once complete, the afferent response has led to
sensitization of the T-cells and B-cells to the specific immunogen. Sensitized = immunocommitted = primed. B-cells can react directly with the immunogen
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agar
(a derivative of sea weed) is generally used to solidify media, but gelatin and even
potato slices have been used.
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why do we grow bacteria on solid media?
Since all cocci appear alike, as do all bacilli, etc., we can't just look at them and tell
which bacteria they are. We must first grow them on solid media to separate them out
into pure culture. There are many types of solid media:
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General "crude grade" media
(nutrient agar, brain-heart infusion, trypticase soy,
etc.) that most bacteria will grow on
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Selective media
contain ingredients that inhibit growth by some bacteria while enhancing growth of others (endo agar, mitis/salivarius, etc.). Inhibitors can be salts,
dyes, detergents, etc.
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Differential media
contain components which identify certain bacteria or groups of bacteria. These are often such things as blood cells, pH indicators, reagents that
change appearance when oxidized or reduced, and so forth.
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Selective/Differential media
combine selective inhibitors or enhancers with
components that identify certain bacteria. These media are commonly used to
diagnose bacterial infections.
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Koch's Postulates of Disease Causation
toassociate a specific bacterium with a specific disease (e.g. septic sore throat is caused by Streptococcus pyogenes).
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Koch's Postulates:
1. The bacterium must be associated with the disease (the bacterium must be found when and where the disease occurs).
2. The bacterium must be isolated in pure culture. This is essential since many bacteria can inhabit the same site (e.g. there are dozens of bacteria species in the throat, gut or skin, etc.).
3. The bacterium must cause the same disease when administered to animals.
4. The bacterium must be re-isolated from the infected animal in pure culture.
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Prions vs Viruses
Though both viruses and prions appear as living beings, they are non living things. They are actually small parasites that need cells of living things to grow and reproduce.
## Footnote
* Viruses and prions are pathogens that cause infections.
* There are many similarities in viruses and prions
* While viruses are made up of proteins and nucleic acids, prions lack in genetic code (nucleic acids)
* Viruses cause lots of diseases while prions have been know to cause brain diseases only.
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saprophytes
A plant, fungus, or microorganism that lives on dead or decaying organic matter.
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internal organelles
A structure or part that is enclosed within its own membrane inside a cell and has a particular function. Organelles are found only in eukaryotic cells and are absent from the cells of prokaryotes such as bacteria. The nucleus, the mitochondrion, the chloroplast, the Golgi apparatus, the lysosome, and the endoplasmic reticulum are all examples of organelles. Some organelles, such as mitochondria and chloroplasts, have their own genome (genetic material) separate from that found in the nucleus of the cell. Such organelles are thought to have their evolutionary origin in symbiotic bacteria or other organisms that have become a permanent part of the cell.
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innate response vs adaptive response cells
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The Cell-Mediated System
The cell-mediated immune response involves cytotoxic T-cells, or killer-T cells. Body cells that have been infected by foreign matter often present components of that material on their surfaces. Killer-T cells recognize these displays and respond by ingesting or otherwise destroying the infected cell. Killer-T cells are also important in the body's defenses against parasites, fungi, protozoans, and other larger cells that might have found their way into the body. The killer-T cells recognize these large invaders by their foreign proteins and then destroy them.
Killer-T cells also produce T memory cells which "remember" a specific protein or antigen. The combination of T-cell and B-cell memory assures the body of familiarity with any antigens or foreign agents that have been present in the body within the last few years. A response to an agent against which the body has already formed memory cells is called a secondary response. All other responses are primary responses.
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The Humoral System
The humoral system of immunity is also called the antibody-mediated system because of its use of specific immune-system structures called antibodies. The first stage in the humoral pathway of immunity is the ingestion (phagocytosis) of foreign matter by special blood cells called macrophages. The macrophages digest the infectious agent and then display some of its components on their surfaces. Cells called helper-T cells recognize this presentation, activate their immune response, and multiply rapidly. This is called the activation phase.
The next phase, called the effector phase, involves a communication between helper-T cells and B-cells. Activated helper-T cells use chemical signals to contact B-cells, which then begin to multiply rapidly as well. B-cell descendants become either plasma cells or B memory cells. The plasma cells begin to manufacture huge quantities of antibodies that will bind to the foreign invader (the antigen) and prime it for destruction. B memory cells retain a "memory" of the specific antigen that can be used to mobilize the immune system faster if the body encounters the antigen later in life. These cells generally persist for years.
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The Immune System: Humoral and Cell-Mediated Immunity
The human immune system is divided into two main parts: humoral immunity, which deals with infectious agents in the blood and body tissues, and cell-mediated immunity, which deals with body cells that have been infected. In general, the humoral system is managed by B-cells (with help from T-cells), and the cell-mediated system is managed by T-cells. Both systems exhibit fascinating complexity and interrelationships that allow them to fine-tune immune reactions to almost any antigen, or molecule that stimulates an immune response.
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When referring to size, what prefixes are used for bateria and viruses?
-meters
which is smaller?
Bacteria are expressed in micrometers whereas viruses are expressed in nanometers.
Viruses are 1000 times smaller.
A micrometer is 1 millionth ( 0.000001 ) of a meter, and a nanometer is 1 billionth ( 0.000000001) of a meter. So the difference in length is 1000. Obviously 1 nanometer is a 1000 times SMALLER than 1 micrometer, or 1 micrometer is 1000 times LARGER than 1 nanometer.
1 micro meter = 1/1000 nano meter
so,
0.001 micrometers = 1 nanometer
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bacterial capsules serve what function?
------- serve as antiphagocytic function, meaning that they protect encapsulated bacteria from being phagocized by leukocytes.
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pathogen
def'n
cause 2 major types of diseases:
A bacterium, virus, or other microorganism that can cause disease.
infectious diseases and microbial diseases.
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genotype v phenotype
An organisims complete collection of genes is referred to as genotype. An organisims complete collection of physical characteristics are known as the oganisims phenotype.
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Another name for acellular microbes are _____ and another name for cellular microbes are \_\_\_\_.
infectious particles and microorganisims
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Explain how to calculate the total magnification of the compound light microscope.
The total magnification of the compound light microscope is calculated by multiplying the magnifying power of the ocular lens by the magnifying power of the objective being used.
140
The resolving power of a transmission electron microscope is what?
A.
approximately 0.2 nanometeres
B.
1 million times better that the human eye
C.
1,000 times better than the resolving power of a compound microscope.
D.
Both A and C
E IS CORRECT
**All of the Above**
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Since viruses are not considered to be living organisims, they are referred to as what?
acellular microbes
infectious particles
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Opportunistic pathogens
do not cause disease under ordinary circumstances, but they have the potential to cause disease should the opportunity present itself.
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What are the three parts of a "true nucleus"?
Neucleoplasm, chromosomes, and a nuclear membrane
144
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hematopoietic system
The blood-making organs, principally the bone marrow and lymph nodes.
146
erythrocyte
red blood cell; corpuscle; one of the formed elements in peripheral blood. Normally, in humans, the mature form is a non-nucleated, yellowish, biconcave disk, containing hemoglobin and transporting oxygen.
mainly made in
147
Lymphocytes
Lymphocytes are small white blood cells that bear the major responsibility for carrying out the activities of the immune system; they number about one trillion. The two major classes of lymphocytes are: B cells, which grow to maturity independent of the thymus, and T cells, which are processed in the thymus. Both B cells and T cells recognize specific antigen targets.
B cells work chiefly by secreting soluble substances called antibodies into the body's fluids, or humors. (This is known as humoral immunity.) Antibodies typically interact with circulating antigens such as bacteria and toxic molecules, but are unable to penetrate living cells. T cells, in contrast, interact directly with their targets, attacking body cells that have been commandeered by viruses or warped malignancy. (This is cellular immunity.)
## Footnote
Although small lymphocytes look identical, even under the microscope, they can be told apart by means of distinctive molecules they carry on their cell surface. Not only do such markers distinguish between B cells and T cells, they distinguish among various subsets of cells that behave differently. Every mature T cell, for instance, carries a marker known as T3 (or CD3); in addition, most helper T cells carry a T4 (CD4) marker, a molecule that recognizes class II MHC antigens. A molecule known as T8 (CD8), which recognizes class I MHC antigens, is found on many suppressor/cytotoxic T cells. In addition, different T cells have different kinds of antigen receptors-either alpha/beta or gamma/delta.
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DNA
**Deoxyribonucleic acid** (DNA) is how the cell encodes information to make all of the macromolecules that it requires. Most of these macromolecules are proteins but some are RNA molecules. From a chemical point of view DNA is a polymer made up of a ribose and phosphate backbone with varible side groups of **Adenine(A), Cytosine(C), Guanine(G), and Thymine(T**). Note that the polymer has a directionality associated with it because on one side of the riobse backbone the phosphate is bound to the 5' position and on the other the phosphate is bound to the 3' position, as illustrated in Figure 1. By convention DNA is represented by a string of A, T, G and C written starting at the 5' end and continuing left to right to the 3'end of the molecule. For example the strand on the left hand side of Figure 1 would be written: CAGT. The strand on the right hand side of Figure 1 would be written ACTG.
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Bone marrow
Bone marrow contains two types of stem cells: hemopoietic (which can produce blood cells) and stromal (which can produce fat, cartilage and bone).
There are two types of bone marrow: red marrow (also known as myeloid tissue) and yellow marrow.
Red blood cells, platelets and most white blood cells arise in red marrow; some white blood cells develop in yellow marrow.
The color of yellow marrow is due to the much higher number of fat cells.
Both types of bone marrow contain numerous blood vessels and capillaries. At birth, all bone marrow is red.
With age, more and more of it is converted to the yellow type.
Adults have on average about 2.6kg (5.7lbs) of bone marrow, with about half of it being red.
Red marrow is found mainly in the flat bones such as hip bone, breast bone, skull, ribs, vertebrae and shoulder blades, and in the cancellous ("spongy") material at the proximal ends of the long bones femur and humerus.
Pink Marrow is found in the hollow interior of the middle portion of long bones. There are several serious diseases involving bone marrow.
In cases of severe blood loss, the body can convert yellow marrow back to red marrow in order to increase blood cell production. The normal bone marrow architecture can be displaced by malignancies or infections such as tuberculosis, leading to a decrease in the production of blood cells and blood platelets.
In addition, cancers of the hematologic progenitor cells in the bone marrow can arise; these are the leukemias.
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protein structure
Primary- amino acid sequence
Secondary- interaction or "R" side chains
Tertiary- effect of environment on protein folding
Quaternary- 2 or more proteins interacting together
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Course of Infection by Stage
Incubation Period
Interval between entrance of pathogen into body and appearance of first symptoms (e.g., chickenpox, 2-3 weeks; common cold, 1-2 days; influenza, 1-3 days; mumps, 15-18 days)
Prodromal Stage
Interval from onset of nonspecific signs and symptoms (malaise, low-grade fever, fatigue) to more specific symptoms (During this time, microorganisms grow and multiply, and client may be more capable of spreading disease to others)
Illness Stage
Interval when client manifests signs and symptoms specific to type of infection (e.g., common cold manifested by sore throat, sinus congestion, rhinitis; mumps manifested by earache, high fever, parotid and salivary gland swelling)
Convalescence
Interval when acute sypmtoms of infection disappear (Length of recovery depends on severity of infection and client's general state of health; recovery may take several days to months)
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cell structure: Gram + vs Gram -
The peptidoglycan layer of gram-positive cells is thicker, and there is no outer membrane or obvious periplasmic space. The peptidoglycan layer of gram-negative cells is thinner, and there is an outer membrane in addition to the cell cytoplasmic membrane. The periplasm is the region between the inner and outer membranes in gram-negative cells.
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Main differences between prokaryotes and eukaryotes:
## Footnote
* Nature and arrangement of genetic material.
* Membrane-bounded organelles.
* Protein synthesis machinery, 70S vs. 80S ribosomes.
* The chemistry of the cell wall (where present).
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Mast Cells
A cell filled with basophil granules, found in connective tissue and releasing histamine during inflammatory and allergic reactions.
Mast cells are located in tissues such as the skin, the lungs, the mouth, the nose and the digestive tract. There are two types of mast cells, those formed from connective tissue and those that are derived from mucosal mast cells.
155
Cytokines
a generic term for nonantibody proteins released by one cell population on contact with specific antigen, which act as intercellular mediators, as in the generation of an immune response.
156
Chemokines
any of a group of low-molecular-weight cytokines, such as interleukin-8, identified on the basis of their ability to induce chemotaxis or chemokinesis in leukocytes (or in particular populations of leukocytes) in inflammation. The group is divided into four subgroups on the basis of genetic, structural, and functional criteria. They function as regulators of the immune system and may also play roles in the circulatory and central nervous systems.
157
chemotaxis
movement toward or away from a chemical stimulus. Chemotaxis is a cellular function, particularly of neutrophils and monocytes, whose phagocytic activity is influenced by chemical factors released by invading microorganisms
158
neutrophils
Human neutrophils are mobile cells that will quickly migrate to sites of injury to help fight infection. They are attracted there by chemical signals released by other cells of the immune system or by invading microbes.
159
polymorphonuclear cell
a leukocyte with a multilobed nucleus, such as a neutrophil.
160
eosinophil
1. A type of white blood cell containing cytoplasmic granules that are easily stained by eosin or other acid dyes. Also called eosinophilic leukocyte, oxyphil, oxyphilic leukocyte.
2. A microorganism, cell, or histological element easily stained by eosin or other acid dyes.
a granular leukocyte having a nucleus with two lobes connected by a thread of chromatin, and cytoplasm containing coarse, round granules of uniform size.
161
basophil
1. any structure, cell, or histologic element staining readily with basic dyes.
2. a granular leukocyte with an irregularly shaped, relatively pale-staining nucleus that is partially constricted into two lobes, and with cytoplasm containing coarse bluish-black granules of variable size.
3. one of the hormone-producing basophilic cells of the adenohypophysis; types include gonadotrophs and thyrotrophs. basophil´ic
