Innate Host Immunity Flashcards
(139 cards)
1
Q
what 2 things mucst pathogens overcome in order to cause disease?
A
- must overcome surface barriers and reach underlying tissues
- must overcome resistance by host
2
Q
what is the first line of defense against disease causing pathogens?
A
surface barriers of host
3
Q
what are the 2 aspects of resistance by host?
A
- nonspecific resistance
2. specific immune response
4
Q
what is the immune system? Define and give function
A
- composed of widely distributed cells, tissues, and organs
2. recognizes foreign substances or microbes and acts to neutralize or destroy them
5
Q
what is immunity?
A
the ability of the host to resist a particular disease or infeciton
6
Q
what is immunology?
A
the science concerned with immune responses
7
Q
what is the nonspecific immune response also called? (3)
A
- nonspecific resistance
- innate immunity
- natural immunity
8
Q
what is the first line of defense of immunity specifically
A
nonspecific immune response
9
Q
what does the nonspecific immune response do?
A
offers resistance to any microbe or foreign material
10
Q
does the nonspecific immune response have any immunological memory?
A
no
11
Q
list 3 other names for the specific immune response
A
- acquired
- adaptive immunity
- specific immunity
12
Q
to what does the specific immune response have resistance?
A
a particular foreign agent
13
Q
discuss the memory of the specific immune response
A
has memory! effectiveness increases on repeated exposure to agent
14
Q
what 2 things are the physical barriers in nonspecific (innate) immunity impacted by?
A
- direct factors
2. indirect factors
15
Q
list 5 direct factors that effect the effectiveness of physical barriers in nonspecific (innate) immunity
A
- nutrition
- physiology
- fever
- age
- genetics
16
Q
list 3 indirect factors that effect the effectiveness of physical barriers in innate (nonspecific) immunity
A
- personal hygiene
- socioeconomic status
- living conditions
17
Q
give an example of personal hygiene as an indirect factor effecting the effectiveness of physical barriers in innate (nonspecific) immunity
A
feral dogs and cats are in good physical condition, so they are more susceptible to disease
18
Q
what are the 2 aspects of nonspecific resistance (innate) that are the first line of defense agiant microbes?
A
- physical barriers
2. host secretions (flushing)
19
Q
what are the 6 physical barriers in innate (nonspecific) resistance?
A
- skin
- mucous membranes
- respiratory system
- gastrointestinal tract
- genitourinary tract
- the eye
20
Q
describe the skin
A
- a strong mechanical barrier to microbial invasion
2. an inhospitable environment for microbes
21
Q
what is the skin made of?
A
keratin produced by keratinocytes in outer layer
22
Q
list 4 reasons why the skin is an ihospitable environment for microbes
A
- attached organisms removed by shedding of outer skin cells
- pH is slightly acidic (most microbes no like)
- high NaCl concentration (most microbes no like)
- subject to periodic drying
23
Q
describe mucous membranes (2)
A
- form protective covering that resists penetration and traps many microbes
- are often bathed in antimicrobial secretions which contain a variety of antimicrobial substances
24
Q
list and describe the function of 3 antimicrobial substances found in mucous membranes
A
- lysozyme: hydrolyzes bonds connecting sugars in peptidoglycan
- lactoferrin: secreted by certain immune cells and sequesters iron (that microbes need for metabolic processes) from plasma and away from microbes
- lactoperoxidase: produces superoxide radicals
25
list the 3 physical barrier aspects of the respiratory system
1. turbulent air flow deposits microbes onto mucosal surfaces
2. mucociliary blanket
3. alveolar macrophages
26
describe how the respiratory system uses a mucociliary blanket as a physical barrier against microbes (3)
1. mucous secretions trap microbes
2. once trapped, microbes are transported away from the lungs on the mucociliary escalator
3. the microbes are then expelled by coughing or sneezing or salivation washes microbes into the stomach for death
27
describe how the alveolar macrophages of the respiratory tract serve as a physical barrier
phagocytic cells in alveoli of lungs eat microbes
28
what are the 3 aspects of the GI tract that function as physical barriers?
1. stomach
2. small intestines
3. large intestines
29
how does the stomach function as a physical barrier in the GI tract?
gastric acid
30
in what 4 ways does the small intestine function as a physical barrier in the GI tract?
1. pancreatic enzymes
2. bile!!
3. intestinal enzymes
4. peristalsis
31
in what 3 ways do the large intestines function as a physical barrier in the GI tract?
1. shedding of columnar epithelial cells
2. secretory IgA
3. normal microbiota (good gut bacteria)
32
in what 3 ways does the genitourinary tract function as a physical barrier?
1. unfavorable environment for foreign microbes
2. flushing with urine and mucus
3. distance barrier of male urethra
33
list the 3 ways that the genitourinary tract is an unfavorable environment for foreign microbes
1. low pH or urine and vagina
2. vagina has lactobacilli
3. urea and other toxic metabolites are end products in urine
34
qhat is the importance of the vagina having lactobacilli in innate immunity?
fetus 1st introduction to microbes usually, so offspring born with vaginal birth have a more robust and diverse initial immunity than C-section offspring
35
describe the distance barreir of the male urethra to pathogens
it is a long way for microbes to travel with no good environment or nutrients, so most die before they get inside from urethra
36
give the 3 ways that the eye functions as a physical barrier
1. mucus-secreting epithelial membrane
2. flushing action of tears
3. lysozyme, lactoferrin, and secretory IgA in tears as well
37
describe chemical mediators in innate (nonspecific) resistance
a variety of defensive chemicals such as defensins and other polypeptides are found in blood, lymph, tears, and other body fluids
38
where are defensive proteins found?
in the blood
39
what is the complement system?
composed of over 30 defensive proteins, located in the blood, that augment or complement the antibacterial activity of antibodies
40
what are the 3 major activities of the complement system?
1. defending against bacterial infections
2. bridging innate and adaptive immunity
3. disposing of wastes
41
what is opsonization?
the process in which microbes are coated by serum components (called opsonins) in preparation for recognition/ingestion by phagocytic cells
42
what do some complement proteins function as? describe this function
opsonins; bind to microbial cells, coating them for phagocyte recognition
43
what are the 3 ways opsonization can occur?
1. coat microbe with antibodies
2. coat microbe with complement proteins
3. coat microbe with antibodies AND complement proteins (big red flag)
44
list 3 other functions of complement proteins
1. function as chemotatic signals that recruit phagocytes to their activation site
2. puncture cell membranes causing cell lysis
3. many complement activities unite the specific and nonspecific arms of the immune system to destroy and remove invading pathogens
45
describe complement activation (3 aspects)
1. complement proteins are produced in inactive forms
2. the complement proteins are activated following enzymatic cleavage
3. the complement proteins MUST be activated in a cascade fashion
46
what are the 3 pathways of complement protein activation?
1. alternative
2. lectin
3. classical
47
what is the alternative complement pathway involved in?
nonspecific defenses against intravascular invasion by bacteria/fungi
48
does the alternative complement pathway happen as a result of immune memory?
no, it just happens
49
what is the alternative complement pathway dependent on?
dependent on interaction of complement with repetitive structures on pathogens
50
how does the alternative complement pathway begin?
with activation of C3 protein
51
what are the 2 most common complement proteins?
C3 and C5
52
what does the alternative complement pathway result in?
formation of the membrane attack complex
53
describe the membrane attack complex, and give what complement pathway it comes from
forms pores/openings in cell wall leading to a loss in pathogen cell homeostasis and destruction of the cell wall, results from the alternative complement pathway
54
what is the lectin complement pathway also called?
the mannose-binding lectin pathway
55
what does the lectin pathway begin with?
activation of C3 and lectin binding
56
what is the lectin complement pathway dependent on?
dependent on interaction of host mannose-binding protein (MBP) with pathogen surfaces
57
what does the lectin binding pathway result in?
enhances phagocytosis by burrowing into mannose
58
what is the classical complement pathway usually dependent on?
usually dependent on antigen-antibody interactions
59
what kind of immunity is the classical complement pathway part of and what does this mean about its speed?
part of acquired immunity, so it is not as fast as other pathways
60
what does the classical complement pathway produce?
cleavage products that participate in opsonization, chemotaxis (to attract phagocytes), and the membrane attack complex
61
what are cytokines?
soluble proteins or glycoproteins that are released by one cell population that act as intracellular mediators or signaling molecules (basically how cells communicate)
62
what are the 3 proposed groups of cytokines based on function?
1. regulators of innate resistance mechanisms
2. regulators of adaptive immunity
3. stimulators of hematopoiesis
63
what is hematopoiesis?
blood immune cell production/differentation
64
what are the 4 types of cytokines based on function?
1. chemokines
2. interleukins
3. interferons
4. colony stimulating factor
65
describe the function of chemokines
stimulate cell migration
66
describe the function of interleukins
released from one leukocyte and act on another leukocyte
67
describe the function of interferons
regulatory cytokines produced in response to infection
68
describe the function of colony stimulating factors
stimulate growth and differentiation of immature leukocytes in bone marrow
69
what is one additional class of cytokine and its function?
tumor necrosis factors: stimulate an imflammatory response
70
list 6 cell types of the immune system
1. granulocytes
2. mast cells
3. monocytes and macrophages
4. dendritic cells
5. lymphocytes
6. leukocytes
71
where are mast cells dderived?
from bone marrow
72
where do mast cells differentiate?
in blood and connective tissue
73
what do mast cells contain?
granules containing histamine and other pharmacologically active chemicals
74
what do mast cells play an important role in?
development of allergies and hypersensitivities, and vasodilation
75
describe how mast cells play a role in vasodilation and what this does
release of their chemicals opens blood vessels, and more blood to the site allows other immune blood cells to come and help in response
76
describe granulocytes (looks)
irregularly shaped nuclei with two to five lobes
77
what is in the cytoplasm of granulocytes?
granuals with reactive substances that kill microbes and enhance inflammation
78
what are the 3/4 types of granulocytes?
1. basophils
2. eosinophils
3. neutrophils
(4) polymorphonuclear neutrophil
79
describe the main function of neutrophils
highly phagocytic
80
how do neutrophils do all that phagocytosis?
circulate in blood then migrate to sites of tissue damage, where they kill ingested microbes with lytic enzymes and reactive oxygen metabolites contained in primary and secondary granules
81
what is the byproduct of neutrophils' cosumption of microbes and subsequent apoptosis?
pus formation
82
what are 2 other cells that are highly phagocytic besides neutrophils?
monocytes and macrophages
83
what are monocytes?
immature macrophages; mononuclear phagocytic leukocytes
84
how do monocytes mature into macrophages?
after circulating for about 8 hours in the blood, they migrate to tissues and mature into macrophages
85
describe macrophages
larger than monocytes and reside in specific tissues
86
how are macrophages named?
according to the tisse in which they reside
87
what do macrophages have to aid in their function?
a variety of surface receptors, including pattern recognition receptors that bind pathogens/microbe associated molecular patterns (PAMPs)
88
where are dendritic cells?
heterogeneous group of cells with neuron-like appendages
89
where are dendritic cells found?
in small numbers in the blood, skin, and mucous membranes of nose, lungs, and intestines
90
what do dendritic cells do that is similar to macrophages?
also express pattern recognition receptors
91
describe the function of macrophages
contact, phagocytose, and process antigens, then display those foreign antigens on their surfaces (antigen presentation)
92
describe lymphocytes
majore cells of the adaptive immune system
93
what do lymphocytes include? (3)
T cells, B cells, and Natural Killer (NK) cells
94
where do T and B lymphocytes differentiate? from what?
in bone marrow from stem cells
95
what are T and B cells activated by?
binding of specific antigen onto lymphocute surface receptors
96
what happens to T and B cells after activation?
replication continues as lymphocytes circulate and enter lymphoid tissue
97
what are memory cells?
activated lymphocytes that do not immediately replicate, but will do so later in the host's life when the antigen is again present
98
where do B lymphocytes mature?
in Bone marrow
99
where do B lymphocytes circulate?
in blood
100
where can B lymphocytes settle?
in lymphoid organs
101
what are B lymphocytes called after maturation? what do they produce?
plasma cells; produce antibodies
102
where do T cells mature?
the Thymus
103
where are mature T cells found? (3)
1. can remain in Thymus
2. can circulate in blood
3. can reside in lymphoid tissue
104
what do T cells require for activation and continuation of replication (like B cells)
antigen binding
105
what 2 types do T cells differentiate into once activated?
1. helper T cells (TH)
| 2. cytotoxic lymphocytes (CTLs)
106
what do T cells do?
secrete and activate cytokines, which are chemicals that have effects on other cells
107
what occurs in the primary organs and tissues of the immune system?
sites where lymphocytes mature and differentiate into antigen-sensitive mature B and T cells
108
what occurs in the secondary organs and tissues of the immune system?
areas where lymphocytes may encounter and bind antigen; followed by proliferation and differentiation into fully mature effector cells
109
what are the 2 primary organs/tissues of the immune system?
1. Thymus
| 2. bone marrow
110
describe what happens in the thymus, a primary organ of the immune system (4)
1. precursor cells move from bone marrow and proliferate
2. thymic deletion removes T cells' self-recognizing antigens
3. remaining celsles become mature T cells
4. the mature T cells enter the blood stream and recognize NONself antigens
111
describe the bone marrow as a primary organ/tissue of the immune system
site of B cell maturation in MAMMALS
112
what does B cell maturation in Bone marrow involve?
removal of nonfunctioig and self-reactive cells
113
describe lymph nodes as a secondary organ/tissue of the immune system
most highly organized lymphoid tissue
114
what do lymph nodes do?
fiilter lymph
115
describe the 2 mechanisms/hardware of lymph nodes to filter lymph
1. microbes and antigens are trapped and phagoctyosed by macrophages and dendritic cells
2. B cells differentiate into memory and plasma cells within lynph nodes
116
what do plasma B cells do?
help destroy pathogens
117
give 2 other secondary tissues/organs of the immune system other than lymph nodes
1. spleen
| 2. lymphoid tissue (skin and mucous associated)
118
what is phagocytosis?
the process by which pahgocytic cells, such as monocytes, tissue macrophages, dendritic cells, and neutrophils, recognize, ingest, and kill extracellular microbes
119
what are the 2 mechanisms for microbe recognition by phagocytes?
1. opsonin-independent (nonopsonic) recognition
| 2. opsonin-dependent (opsonic) recognition
120
what can greatly increase phagocytosis?
opsonization
121
describe opsonin-DEpendent phagocyte pathogen recognition
phagocytes recognize serum proteins attached to pathogens (the big red flag to attract help)
122
describe opsonin-INdependent phagocyte pathogen recognition (2)
1. common pathogen components are non-specifically recognized to activate phagocytosis, with signalling mechanism now involved
2. involved nonspecific/specific receptors on phagocytes
123
describe opsonin INdependent phagocyte pathogen recognition, VERY generally
body can still find pathogens, it just may take longer to find them and recruit helpers for the immune attack
124
describe intracellular digestion of microbes
once bound, microbes can be internalized and delivered to a lysosome to become a phagolysosome
125
what occurs once a lysossome becomes a phagolysosome?
respiratory burst reactions occur
126
what does a phagolysosome produce and what does this do?
produces toxic products like hydrogen peroxide which can kill invading microbes
127
why is antigen presentation an important process?
because it allows wandering lymphocytes to become activated
128
what does antigen presentation link?
specific and nonspecific immune responses
129
what is inflammation? what can it be caused by?
nonspecific response to tissue injury, can be caused by pathogens or physical trauma
130
what is the immediate response of the body to injury or cell death?
acute inflammation
131
what are the 5 cardinal signs of inflammation?
1. redness (rubor)
2. warmth (calor)
3. pain (dolor)
4. swelling (tumor)
5. altered function (functio laesa)
132
describe acute inflammation
the release of inflammatory mediators from injured tissue cells initiates a cascade of events which result in the 5 cardinal signs of imflammation
133
what are the 4 chemical mediators involved in acute inflammation?
1. selectins
2. integrins
3. chemotaxins
4. kallikreins
134
what are selectins in acute inflammation? what do they do?
cell adhesion molecules on activated capillary endothelial cells, slow down circulating neutrophils to keep in needed areas
135
what are integrins in acute inflammation?
adhesion receptors on neutrophils
136
what are chemotaxins in acute inflammation? what do they do?
chemotactic factors released by injured cells, recruit immune cells to the area and trigger responses
137
what are kallikreins in acute inflammation?
enzymes that loosen tight junctions, involved in pain response
138
what 2 processes occur in acute inflammation?
1. margination
| 2. diapedesis/extravasion
139
what do mast cells do in the acute inflammatory response?
release histamines to help with dilation to increase blood flow and loosen tight junctions to allow neutrophils into affected area
