Exam II Review Flashcards
(158 cards)
1
Q
Describe innate and adaptive immunity in terms of their specificity
A
Innate is general, first and second lines of defense, recognizes things like peptidoglycan or flagella (general pathogenic characteristics)
Adaptive is specific, utilizes humoral (antibodies, B cells), and cell-mediated responses (T cells, helper and cytotoxic)
2
Q
Skin is one of the first lines of defense for innate immunity, why can’t most pathogens penetrate the skin?
A
Dry, acidic, and salty
3
Q
What do mucous membranes contain that works as the first line of defense for innate immunity, and how does it work?
A
Lysozyme: works by cleaving between NAG and NAM of peptidoglycan
Lactoferrin: iron scavenging (pathogens contain siderophores)
Lactoperoxidase and pH modification also possible
4
Q
What is the second line of defense for the innate immune system?
A
Interferons [alpha, beta, and gamma]
5
Q
Which interferon is responsible for enhanced phagocytic activity? (acts on bacteria)
A
IF-gamma
6
Q
Which interferon is responsible for affecting neighboring cells and responds to viral infection?
A
IF-alpha and IF-beta
7
Q
What are the innate immune defenses of the respiratory system?
A
mucous and ciliated cells in the nose and pharynx work to move things toward the throat to be coughed out
lower respiratory tract protected by alveolar macrophages and mucociliary escalator
8
Q
What are the innate immune defenses of the eyes?
A
Lacrimal apparatus: produces tears containing lysozyme that can drain out the nose
also eyelashes, blinking
9
Q
What is the function of eosinophils?
A
Protect us from large parasitic infections like helminths and roundworms using granzymes and perforin
10
Q
What type of cells may act as phagocytic cells?
A
macrophages, dendritic cells, neutrophils
11
Q
How do the chemical mediators of inflammation function?
A
prostaglandins release histamine and bradykinins which cause vasodilation and increased capillary permeability, resulting in edema/swelling
12
Q
How does fever enhance our innate immune response?
A
By increasing metabolism and transferrins
13
Q
Who secretes transferrins (host or pathogen) and what do they do?
A
Host secretes transferrins which prevents free iron from being taken up by pathogens with siderophores
14
Q
When is fever detrimental? What cells are most sensitive?
A
If body temp goes too high; neurons/brain cells are the most sensitive to body temperature
15
Q
What are the important chemical mediators of fever?
A
Activation of pituitary gland causing release of prostaglandins; interleukin-1 leads to T cell activation
16
Q
Where do the 3 complement pathways converge?
A
C3
17
Q
What are the 3 main activities of the complement?
A
- Formation of the membrane attack complex (MAC) which is dependent on C5 activation, leading to C6-9
- Opsonization - attraction of phagocytic cells
- Enhances inflammation
18
Q
What are PAMPs and name examples
A
Pathogen Associated Molecular Patterns
LPS, Peptidoglycan, Flagella
19
Q
What are TLRs and how do they work
A
Toll-like receptors; act as ligand-gated receptors that recognize PAMPs; can be located anywhere in/on the cell
*She gave the example of an inflammation response to TLR binding a PAMP
20
Q
What is the difference between a TCR and a TLR?
A
TCR = T cell receptors; located on helper T cells and cytotoxic T cells ONLY
TLR = Toll-like receptor; found on all cells
21
Q
Which will generate stronger response: T-independent B cell activation, or T-dependent B cell activation?
A
T-dependent B cell activation, which requires helper T cells. T helper cells require two signals in order to recognize a particular pathogen
22
Q
Do helper T cells bind to free antigens?
A
NO
They only bind to antigens coupled with MHC class II molecule (on APC)
23
Q
Where are MHC class I molecules found? What occurs if they are missing? What about when antigen is bound?
A
all nucleated cells; if they are missing, natural killer cells are activated. When antigen is bound they will activate cytotoxic T cells
24
Q
True or false: there is only one pathway through which cytotoxic T cells can initiate cell death
A
False!
Cytotoxic T cells or Natural Killer cells can cause apoptosis, cell death, or necrosis
*Apoptosis is preferred response
25
What are the 3 types of APCs that exhibit MHC class II?
B cells, dendritic cells, and activated macrophages
26
What type of antigen is capable of linking MHC class II and T cells together, causing activation of T cell in the absence of a specific antigen?
Superantigen
27
There are 2 signals necessary to T cell activation, the first signal involves co-receptors. What are co-receptors?
CD4+ = helper T cells
CD8+ = cytotoxic T cells
28
Which type of T cell requires MHC class I presenting an antigen to the T cell receptor?
Cytotoxic T cell with co-receptor CD8+
this will lead to one of several pathways toward cell death
29
what type of cells produce antibodies?
plasma cells
30
What is the structure of an antibody?
Made up of light chains and heavy chains with two domains: variable region and constant region
31
Which region of an antibody binds to the antigen? Which region binds to the surface of the antibody?
Variable region binds to the antigen, constant region binds to the antibody itself
32
Where would you find an antibody such as IgM, IgG, IgA, IgD, or IgE?
In the blood!
33
Which antibody is the first to be produced in response to an infection? Second? What is the process called when the antibody present changes?
First is IgM - agglutination, Second is IgG
Class switching occurs between IgM and IgG
34
Describe the concept of combinatorial joining
Random deletion events in which variable exons are spliced together with constant region. The constant region dictates the class of antibody prior to forming final mRNA strand. Overall purpose is to create diversity of antibodies
35
What areas of the body should be free of microbes?
Lower respiratory tract, kidneys and beyond (bladder), blood, CSF
36
Where would you find the most normal flora?
intestines
37
What is a reservoir for Shigella?
water
*Reservoirs can be inanimate or animate!
38
Define vector
organism that spreads pathogen from one host to another; for example: arthropods (fleas, ticks, lice)
39
Fomite
inanimate object that can be contaminated with a pathogen
40
What are the stages of disease in order?
incubation period, prodromal stage, period of illness (may plateau or continue - chronic, convalescence
41
What is the portal of entry for an opportunistic pathogen invading a surgical site or abscess?
Parentaral route
42
Name 5 virulence factors that contribute to adherence
Fimbriae, pili, M proteins, capsules, and biofilms
43
Describe catalase
reactive oxygen species that are converted into water and gas; upregulation of catalase occurs in the phagolysosome
44
Describe coagulase
Converts fibrinogen into fibrin, forming wall around pathogen so phagocytic cells cannot get to it
45
What do proteases and kinases do?
proteases cleave immunoglobulins, kinases break down fibrin clots
46
Which pathogen is known to exhibit antigenic variation?
Neisseria with its varying pilum proteins
47
Which pathogens exhibit intracellular growth?
Chlamydia, Rickettsia, Shigella, Listeria
48
Which pathogen utilizes host cell actin?
Shigella
49
Name some exotoxins from organisms discussed in class
Botulinum toxin, Shigatoxin, Cholera toxin, Pertussis toxin, Superantigens, Enterotoxin
50
What does the pertussis toxin do?
causes mucous production, then cytotoxin kills ciliated cells which leads to paroxysmal cough
51
Lysogenic conversion occurs when phage infection brings in virulence factors. Name 2 organisms that exhibit lysogeny
S. pyogenes (strep throat) can lead to scarlet fever, rheumatic fever, cholera. Staphylococcal enterotoxin also.
52
What is the function of an Opa protein?
prevents T cell proliferation
53
Define bacteremia, toxemia, and viremia
Bacteria in the blood
Toxins in the blood
Viruses in the blood
54
What is the difference between infection and intoxication?
infection occurs when colonization by an organism results in disease
intoxication occurs due to the presence of a toxin (toxemia)
55
Compare botulism and tetanus toxins
Both have AB toxins, both are neurotoxins, both produced by clostridium species, both act on neuromuscular junction of synapses
56
Describe Botulism
flaccid paralysis due to blocked release of ACh
57
Describe Tetanus
rigid paralysis due to inhibited release of GABA and glycine
58
Toxins are named by activity. Describe an AB toxin
AB toxins have Active region and Binding region
59
What is an obligate intracellular parasite that has an RB and an EB?
Chlamydia
60
Why is Shigella unique for an enteric?
It lacks a flagellar antigen so it is non-motile; other enterics have flagella
61
What are K, H, and O antigens?
O is LPS on surface
H is flagella
K is capsule
62
What are 5 modes of transmission
```
airborne
contact
vehicle
vector-borne
vertical ---- example: Listeriosis!!
```
63
In what type of tests might fluorescence be used?
microscopy, cell sorting, flow cytometry
64
What is required for crossing the species barrier?
antigenic shift with recombination
65
Naturally acquired active immunity
Type of specific immunity a host develops after exposure to a foreign substance (consequence of prior infection)
66
Naturally acquired passive immunity
Transfer of antibodies, e.g., mother to fetus across placenta, or through breastfeeding
67
Artificially acquired active immunity
Intentional exposure to a foreign material (vaccination)
Goal is to stimulate antibody production
68
Artificially acquired passive immunity
Preformed antibodies or lymphocytes produced by one host are introduced into another host
Goal is to give antibodies directly
For example: immune globulin therapy
69
What type of immunity is stimulated by vaccinations/immunizations?
Artificially acquired active immunity
70
What type of organism is contained in an attenuated vaccine?
Live but avirulent (mutated)
71
What type of organism is contained in an inactivated vaccine?
Dead
72
What is a DNA vaccine?
DNA is directly introduced into host cell via gene gun, where DNA is taken into nucleus and pathogen's DNA fragment is expressed so that host immune system can respond
73
Describe acute, chronic, and latent disease
Acute: symptoms develop rapidly
Chronic: disease develops slowly
Latent: disease with a period of no symptoms when the causative agent is inactive
74
Communicable disease
A disease that is spread from one host to another (a contagious disease is one that is EASILY spread)
75
Noncommunicable disease
A disease that is not transmitted from one host to another (for example: botulism)
76
What is a nosocomial infection and what is the most common type?
Hospital acquired infection often due to normal flora of patient or caregiver acting as opportunistic pathogens
Most common is urinary tract infection
Others include: surgical site infections, bloodstream infections (IVs), pneumonia (artificial airways)
77
Endemic disease
Maintains a relatively steady low-level frequency at a moderately regular interval
78
Hyperendemic disease
Gradual increase in occurrence frequency above endemic level but not to epidemic level
79
Epidemic
Sudden increase in frequency above expected number
Index case is the first case in an epidemic
80
Pandemic
Increase in disease occurrence within large population over wide region (usually worldwide)
81
Name the 5 consequences of antibody binding of an antigen
```
Agglutination
Opsonization
Complement activation
Neutralization
Antibody-dependent cell-mediated cytotoxicity
```
82
Define agglutination, one of the consequences of antibody binding of antigen
Agglutination reduces number of infectious units to be dealt with by sticking together
83
Define opsonization, one of the consequences of antibody binding of antigen
Coating antigen with antibody, enhancing phagocytosis
84
Define complement fixation, one of the consequences of antibody binding of antigen
Addition of complement causes inflammation and cell lysis
85
Define antibody-dependent cell-mediated immunity, one of the consequences of antibody binding of antigen
Antibodies attached to target cell cause destruction by macrophages, eosinophils, and NK cells
86
Define neutralization, one of the consequences of antibody binding of antigen
Blocks adhesion/attachment of bacteria, viruses, or toxins to mucosa
87
When using hemagglutination testing, what is the positive result and why?
A positive result would be NO agglutination, meaning that the antibodies are present and preventing agglutination
88
What is the indicator for complement fixation testing?
RBCs (hemolysis)
89
Is complement fixation test direct or indirect?
Indirect, because looking for the presence of antibodies
90
What is a positive result in the complement fixation test?
No hemolysis, because the complement is tied up in the antigen-antibody reaction
91
What is the indicator for the ELISA test?
Peroxidase enzyme, reaction is visualized by addition of chromogen (color change)
(ELISA = Enzyme-Linked Immunosorbent Assay)
92
What is adsorbed to the bottom of the well in the first step of a direct ELISA? What about an indirect ELISA?
Direct ELISA: antibody is adsorbed to the well, looking for antigen
Indirect ELISA: antigen is adsorbed to the well, looking for antibody
93
What indicates a positive result during a neutralization test?
Indicator is cell damage; if antitoxins bind, they will be neutralized and we will see undamaged cells which is a positive result
94
What would you assume had happened if a patient was not producing antibodies at one time, but two weeks later they were?
Seroconversion
95
What type of serological test detects antigens from patient sample?
Direct
96
What type of serological test detects antibodies in patient serum?
Indirect
97
What method is used for identification of bacteria based on number of plasmids and their molecular weight?
plasmid fingerprinting
98
What type of immunofluorescence involves unknown antigen added to antibody labeled with fluorescent dye resulting in visible fluorescence?
Direct, because the antibody is binding directly to the pathogen
99
What type of immunofluorescence involves known antigen tested in different serums to see if there is fluorescence that occurs?
Indirect
100
What type of antibody is produced by a hybridoma cell as an "immortal" cancerous B cell fused with an antibody-producing normal B cell?
Hint: these recognize a single epitope
Monoclonal antibodies
These are visualized with fluorescence
101
Describe endotoxins in terms of their source, metabolic product, chemical make-up, ability to cause fever, ability to be neutralized by antitoxin, and magnitude of LD50
```
Source: gram-negative
Metabolic product: present in LPS of outer membrane
Chemistry: lipid
Fever? YES (pyrogenic)
Neutralized by antitoxin? NO
LD50: relatively large
```
102
Describe exotoxins in terms of their source, metabolic product, chemical make-up, ability to cause fever, ability to be neutralized by antitoxin, and magnitude of LD50
Source: mostly gram-positive
Metabolic product: by-products of growing cell
Chemistry: protein (soluble, heat-labile)
Fever? NO
Neutralized by antitoxin? YES
LD50: small (among the most lethal substances known)
103
What does the hyaluronidase enzyme do in terms of resisting host defenses?
Hydrolyzes hyaluronic acid (found in connective tissue)
104
What is the function of invasins?
Establish a niche, colonize an area, invade host cell defenses and prevent phagocytosis (innate), prevent antibody binding (acquired), and prevent attachment
105
Members of normal microbiota that produce disease under certain circumstances, such as when they are misplaced to an area they are not normally found
Opportunistic pathogens
106
What is a zoonose and give examples
Infections passed from animal to human
SARS (bats), tuberculosis (horses, cattle), typhus fever (rats)
107
Define the symbiotic relationship: Commensalism and give an example
One organism benefits while the other is unaffected/unharmed
Example: Staph Aureus in your nose
108
Define the symbiotic relationship: Mutualism and give and example
Both organisms benefit
Example: E. Coli in the gut benefit from rich nutrients, while they produce vitamins B and K for host benefit
109
Define the symbiotic relationship: Parasitism and give an example
One organism benefits at the expense of the other (host is harmed)
Example: H1N1
110
```
All of the following are involved in keeping the lower respiratory tract free of microorganisms except:
A. Ciliary escalator
B. Epiglottis
C. Alveolar macrophages
D. Lacrimal apparatus
```
D. Lacrimal apparatus
111
```
Which of the following pathways for complement activation is generally dependent upon the formation of antigen-antibody complexes?
A. The classical pathway
B. The alternative pathway
C. The lectin pathway
D. All of the above
```
A. The classical pathway
112
```
Which leukocytes function to produce toxins against certain parasites?
A. Lymphocytes
B. Basophils
C. Eosinophils
D. Neutrophils
```
C. Eosinophils
113
```
Which host defense is more effective against gram positive bacteria than gram negative bacteria?
A. Mucus
B. Sebum
C. Gastric juice
D. Lysozyme
```
D. Lysozyme
Because of thicker layer of peptidoglycan, it will have a greater impact -- gram negative are protected by outer membrane
114
Natural killer cells specifically kill which of the following?
A. Gram positive
B. Gram negative
C. Fungi protozoa
D. Tumor cells and cells infected by microorganisms
D. Tumor cells and cells infected by microorganisms
115
```
Each of the following is an effect of complement activation, except:
A. Opsonization
B. Increased phagocytic activity
C. Interference with viral replication
D. Increased blood vessel permeability
```
C. Interference with viral replication
116
```
Eosinophils defend against protist and helminth parasites by:
A. Phagocytosis
B. Complement activation
C. Antibody production
D. Releasing perforin and lytic enzymes
```
D. Releasing perforin and lytic enzymes
117
Which of the following is INCORRECTLY matched?
A. PAMP - peptidoglycan
B. TLR - stimulation of the inflammatory response
C. Histamine - vasodilation
D. None of the above
D. None of the above
118
Class II major histocompatibility complex molecules are found on all of the following except:
A. B cells
B. T cells
C. Dendritic cells
D. None of the above, all have MHC class II molecules
B. T cells
119
Which of the following releases histamine?
A. Mast cells
B. Basophils
C. Plasma cells
D. Mast cells and basophils
D. Mast cells and basophils
120
Which of the following would you not find as normal flora in the nasopharynx?
A. Streptococcus pneumoniae
B. Escherichia coli
C. Neisseria meningitidis
D. Haemophilus influenza
B. Escherichia coli
121
Which of the following areas of the human body is/are NOT normally free of microorganisms?
A. Upper respiratory tract
B. Intestinal tract
C. Eyes
D. All of the choices
D. All of the choices
122
An inanimate object that may be contaminated with a pathogen is called a:
A. Vector
B. Fomite
C. Zoonose
D. Commensal
B. Fomite
123
True or false: Generally, exotoxins tend to be more heat stable than endotoxins
False
Exotoxins tend to be more heat LABILE because they're made up of protein
124
Antibody molecules that are produced by a single hybridoma clone are called:
A. Human antibodies
B. Monoclonal antibodies
C. Hybrid cells
D. Identical antibodies
B. Monoclonal antibodies
125
What is the most common type of nosocomial infection?
A. Lower respiratory infections
B. Postoperative infections
C. Bacteremia infections
D. Urinary tract infections
D. Urinary tract infections
126
Which of the following measures is NOT used to prevent nosocomial infections?
A. Aseptic technique
B. Frequent handwashing
C. Increased use of antibiotics
D. Education of staff
C. Increased use of antibiotics
127
What organism is the most important reservoir for the Borrelia burgdorferi?
A. Tick
B. Rabbit
C. Squirrel
D. Field mouse
D. Field mouse
128
In what stage of syphilis do gummas develop?
A. Primary
B. Secondary
C. Tertiary
D. Latent
C. Tertiary
129
Which urinary tract bacteria can cause headaches, fever, and possible kidney failure as a complication?
A. Escherichia coli
B. Staphylococcus saprophyticus
C. Leptospira interrogans
D. Neisseria gonorrhoeae
C. Leptospira interrogans
**E. Coli can cause UTIs but it is not a urinary tract bacteria
130
True or False: M protein enhances the virulence of streptococcus by preventing phagocytosis
True
*M proteins function in attachment AND prevention of phagocytosis
131
A nosocomial infection is:
A. Always caused by medical personnel
B. Always caused by pathogenic bacteria
C. Always present, but is not observed in times of hospitalization
D. Acquired during the course of hospitalization
D. Acquired during the course of hospitalization
132
True or False: An endemic disease is constantly present in a population
True
133
Which item is from the patient in a direct ELISA test?
A. Substrate for the enzyme
B. Antigen
C. Antihuman immune system
D. Antibodies against the antigen
B. Antigen
134
Purified protein from Bordetella pertussis is used in a(n):
A. Attenuated whole-agent vaccine
B. Nucleic acid vaccine
C. Subunit vaccine
D. Toxoid vaccine
C. Subunit vaccine
135
Bacillary dysentery is caused by:
A. Staphylococcus
B. Shigella
C. Salmonella
D. Clostridium
B. Shigella
136
What is the main reservoir for Yersinia pestis?
A. Deer
B. Rodents
C. Small mammals
D. Rabbits
B. Rodents
137
C. tetani causes the disease Tetanus by producing a(n):
A. Capsule
B. Endotoxin
C. Exotoxin
D. Enzyme
C. Exotoxin
138
Which urinary tract bacterium can cause headaches, muscle aches, fever, and possible kidney failure as a complication?
A. Escherichia coli
B. Staphylococcus saprophyticus
C. Leptospira interrogans
D. Neisseria gonorrhoeae
C. Leptospira interrogans
139
What is the etiological agent for the disease that has catarrhal, paroxysmal, and convalescence stages?
A. Borrelia
B. Streptococcus
C. Mycobacterium
D. Bordetella
D. Bordetella
140
All gram negative bacteria contain:
A. Exotoxins
B. Endotoxins
C. Siderophores
D. IgA protease
B. Endotoxins
141
C. Tetani causes the disease Tetanus by producing a(n)
A. Capsule
B. Endotoxin
C. Exotoxin
D. Enzyme
C. Exotoxin
142
Septic shock can result from using antibiotics to treat
A. Fungal infections
B. Viral infections
C. Protozoan infections
D. Gram negative bacterial infections
D. Gram negative bacterial infections
143
Arthropods provide a portal of exit for microbes in:
A. Skin
B. Blood
C. Respiratory tract
D. Genitourinary tract
B. Blood
144
What is the clonal selection theory?
States that each lymphocyte has membrane-bound immunoglobulin receptors specific for particular antigen and after the receptor is engaged, proliferation of the cell occurs such that a clone of antibody producing cells is produced
145
What is the clonal deletion theory?
The elimination of certain T cell populations in the thymus that have specificity for self-antigens (forbidden clones)
146
Describe IgG in terms of its valence, where it is found, and function
Monomer - bivalent (2 binding sites)
Capable of complement fixation and crossing the placenta
Found in blood, lymph, and intestine
Enhances phagocytosis, neutralizes toxins and viruses, and protects fetus and newborn
**second antibody to appear in response to infection (M is first)
147
Describe IgM in terms of its valence, where it is found, and function
Pentamer - (10 binding sites)
Capable of complement fixation
Found in blood, lymph, and on B cells
Agglutinates microbes, first antibody introduced in response to infection
148
Describe IgA in terms of its valence, where it is found, and function
Dimer (4 binding sites)
Found in secretions
Functions in mucosal protection
149
Describe IgD in terms of its valence, where it is found, and function
Monomer (2 binding sites)
Found in blood, lymph, and B cells
Functions in initiation of immune response on B cells
150
Describe IgE in terms of where it is found and its function
Found on mast cells, on basophils (histamine), and in blood
| Functions in allergic reactions; lysis of parasitic worms, opsonization
151
During intracellular digestion, the phagosome fuses with lysosome to form ______, leading to degradation with hydrolytic enzymes and H2O2
Phagolysosome
152
What are the cardinal signs of inflammation?
```
Redness
Warmth
Pain
Swelling/edema
Altered function
```
153
Innate, nonspecific response to tissue injury caused by pathogen or physical trauma; it is the immediate response of the body to injury or cell death
inflammation
154
What activates the classical pathway of complement system?
Antigen: antibody complexes (pathogen surfaces)
155
What activates the Lectin pathway of complement system?
Mannose-binding lectin binds mannose on pathogen surface
156
What activates the alternative pathway of complement system?
Pathogen surfaces - activation of C3 forms MAC
157
What innate immune defense kills infected target cells by releasing granules that contain perforin and granzymes? In other words, helps protect cells that have not been able to produce "self" tag?
Natural Killer (NK) cells
*Phagocytes then kill the infected microbes*
158
What are the innate functions of the gastrointestinal immune system?
Gastric acid in the stomach
Pancreatic enzymes, bile, GALT, normal microbiota, and peristalsis and shedding in the intestines
