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Immunology > Test 3- L11 > Flashcards

Test 3- L11 Flashcards

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1
Q

What kind of immunity is important for helping with extracellular pathogens

A

Humoral immunity- mediated by antibodies, complement proteins

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2
Q

What is important for helping with intracellular pathogens

A

Cellular immunity

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3
Q

What are the possible outcomes of infection

A

Protective immunity, partial incomplete or temporary protection, no immunity (tetanus), death, development of a deleterious host immune response

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4
Q

What are the 2 types of immunity you can get from the pathogen

A

Sterilizing immunity- completely removing pathogen from the body
Non-sterilizing immunity- herpes virus (not entirely eliminated- comes back with stress)

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5
Q

Outcomes of infection- (1)Host survives with partial, incomplete, or temporary immunity & (2)Host survival with no immunity examples

A

1- Influenza- subsequent exposure to the same pathogen is less severe
2- Tetanus- Immune response to subsequent exposure to same pathogen are identical to the first

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6
Q

Outcomes of infection- (1) death, (2) development of a deleterious host immune response, (3) alteration of the immune response, (4) autoimmune response examples

A

1- HIV
2- Scarring TB- damage to normal tissue
3- EBV makes viral IL-10 to encourage a Th2 response instead of Th1 resulting in increased infection
4-Klebsiella -> ankylosing spondylitis
Campylobacter jejuni -> Guillain Barre syndrome

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7
Q

What cells help in combating intracellular pathogens

A

NK cells- identify lack of self that some viral infections produce via downregulation of HLA-1

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8
Q

Time course of infection

A
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9
Q

2 common extracellular pathogens

A

Strep, Staph

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10
Q

2 types of intracellular pathogens and their types

A

Obligate intracellular- Chlamydia, Rickettsia
Facultative intracellular- Salmonella, Mycobacteria

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11
Q

Humoral immunity combats

A

Extracellular pathogens

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12
Q

Cell-mediated immunity combats

A

Intracellular pathogens

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13
Q

Examples of humoral immunity & extracellular pathogens

A

Antibodies, antibody/phagocytosis, compliment, lysozyme

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14
Q

Examples of cell-mediated immunity & cells to kill intracellular pathogens

A

TH1 cells (IFN gamma), CD8+ T cells (killvia peptide presentation), NK cells, anti-viral state (generated by cytokines)

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15
Q

Once a pathogen is inside a host cell it is protected against what & what is used to identify and kill it

A

The actions of complement and antibodies, cellular immune mechanisms are needed to recognize that the cell is infected
and eliminate it

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16
Q

The 5 primary means of defense against extracellular bacteria
are:

A

1- Opsonizing antibody and phagocytosis
2-Neutralizing antibody
3-Complement (classical, MBL, and alternative pathways)
4- ADCC (antibody-dependent cell cytotoxicity
5-IgA production

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17
Q

Opsonizing antibody and phagocytosis is important for mediating attack by

A

Encapsulated bacteria- opsonizing antibody directed against
the capsule. When deposited along with complement C3b on the surface of an extracellular pathogen, uptake by phagocytes is greatly enhanced.

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18
Q

Clinical examples of the
importance of phagocytosis in host defense are:

A

Macrophages in the reticuloendothelial system
engulfing bacteria in the blood (sepsis), neutropenic patients

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19
Q

Neutropenic patients are highly susceptible to infections with

A

Extracellular pathogens

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20
Q

Neutralizing antibody does what

A

Inhibits attachment to receptors on host tissue

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21
Q

Complement (classical, MBL, and alternative pathways) is good for what

A

Bacterial cell lysis and opsonization

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22
Q

ADCC is good for what

A

Many different types of pathogenic bacteria

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23
Q

IgA production does what

A

Major means that the host uses to defend against extracellular pathogen infections at mucosal surfaces

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24
Q

Many extracellular bacteria avoid the harsh environment of the circulatory system and/or
within tissues by doing what

A

Adhering to, colonizing, and infecting only mucosal surfaces where the amount of phagocytic cells and complement are very low

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25
Many extracellular bacteria avoid the harsh environment of the circulatory system and/or within tissues- examples are:
Bacteria that cause cholera, pertussis, and diphtheria
26
Bacteria that cause cholera, pertussis, and diphtheria- what are important for combating these pathogens
Mucosal immunity (IgA)- neutralizes toxins
27
What are the 2 types of toxins produced by bacteria
Endotoxins, exotoxins
28
Endotoxins (LPS/LOS) are produced by
Gram negative bacteria- cannot be made by a toxoid
29
LPS is an exogenous pyrogen that induces sequential production of what endogenous pyrogens
IL-1, TNF-α, and IL-6, and thus, causes fever
30
LPS mediates what kind of shock & comes from what
Septic/ endotoxic shock via IL-1, TNF-α, and IL-6 induced cytokine storm (makes too much of them)
31
Endotoxin (LPS/LOS) activates what pathway
Alternate complement pathway
32
Endotoxin (LPS/LOS) biological activity
BROAD biological activity
33
Endotoxin (LPS/LOS) doesn't induce neutralizing antibody but may induce:
Polyclonal B cell stimulation
34
Endotoxin (LPS/LOS) cannot be made into what
A toxoid
35
What is a toxoid
Inactive form of a toxin we can create vaccines by using
36
Exotoxins are produced by
Either gram negative bacteria or gram-positive (most often) bacteria
37
Only certain exotoxins called _______ directly induce cytokine release through activation of T cells
Superantigens- release large quantities of proinflammatory cytokines via too many T cells (TOXIC SHOCK)
38
Exotoxin biological activity
Specific pharmacological activity depending upon the toxin- specific T cells get targeted
39
Exotoxins are generally active at what levels
Levels that are not immunogenic
40
Many Exotoxins can be converted into what
Toxoids
41
Exotoxins- disease doesn't necessarily lead to what
Protective immunity- so we use toxoids for immunizations
42
What are virulence factors
Substances produced by a pathogenic organism that enables it to cause disease
43
Virulence factors are ______ and are targets for ______
Capsules/ toxins, vaccine development
44
What are examples of current vaccines that target the immune response against virulence factors
Diphtheria (toxin), tetanus (toxin), pertussis (toxin), flu type B (capsule) and strep. pneuomoniae (capsule)
45
Immunity to intracellular bacteria is primarily mediated by
T lymphocytes
46
What are the primary T lymphocytes that mediate immunity to intracellular bacteria
CD4+ T helper-1 lymphocytes
47
What do CD4+ T helper-1 lymphocytes produce
IFN-γ and other phagocyte-activating factors are of primary importance in resolving infections with obligate intracellular bacteria
48
Which of the following molecules is most important for immunity from an infection with an encapsulated bacterium (Strep.). 1. IFNα 2. IgG 3. IgE 4. HLA class I 5. IL-12
1. IFNα-viral (phagocytosis) **2. IgG- can opsonize- important for getting ahold of encapsulated bacteria 3. IgE- Helminth 4. HLA class I- Intracellular 5. IL-12- Th1 response
49
Superantigens stimulate an immune response that is composed of 1. A polyclonal antibody response 2. A monoclonal antibody response 3. A polyclonal T cell response 4. A monoclonal T cell response
3. A polyclonal T cell response Polyclonal/monoclonal: how many T cell or B cell clones are being activated
50
Examples of facultative vs. obligate intracellular bacteria
Facultative (mycobacterium)- can live outside or inside cells Obligate (Chlamydia)- must be in cells to be pathogenic
51
What is critical for combating intracellular pathogens
Activation of CD4+ Th1 and production of IFNγ
52
What are the 2 categories of interferons & what do they include
Type 1: IFN-α and IFN-β Type 2: IFN-γ
53
IFN-α and IFN-β are considered what
Non-immune interferons (fibroblast interferons)
54
IFN-α and IFN-β are produced by what cells
Almost all nucleated cells of the body upon infection with a virus or other stimulus
55
IFN-γ is produced by what cells
T-lymphocytes and NK cells
56
Type 2 (IFN-γ) encourages what type of response
Phagocytosis & Th1 response
57
5 type 1 and type 2 interferon anti-bacterial (IFNα/β/γ) effects on non- macrophage cells
1-Restriction of protein synthesis 2-Decrease membrane fluidity 3-Induces iNOS and O2- 4-Altered metabolism 5-Increased HLA class I –leads to increased CTL activity
58
Activated macrophages express what
HLA1 & HLA2
59
Th1 cells secrete_____ to stimulate macrophages to kill ______ pathogens
IFNγ, intracellular
60
Synergistic effects of host and pathogen factors to activate macrophages
61
Activated macrophages are characterized by several things to include, but not limited to: (Type 2 interferon IFNγ only)
-Increased cytoplasmic volume -Increased respiratory burst -Increased HLA class I and II expression (enhanced antigen presentation) -Increased C3b and Fc receptors on surface of macrophage -Increased metabolism -Induces iNOS and O2-
62
Cytotoxic cells in intracellular bacterial infections- early in response
NK and γ/delta TCR+ T lymphocytes (innate)
63
Cytotoxic cells in intracellular bacterial infections- later in response
-CD4+ Th1 activation (IFN-γ and IL-2) -CD8+ CTLs recognize processed antigen -Each of above may produce significant IFN-γ quantities
64
What are 2 cytolytic cells (breakdown target cell)
NK cells and CD8+ T cells
65
What responses are critical for eradicating intracellular bacteria (Chlamydia)
Th1 mediated responses
66
Cytotoxic T lymphocytes have been shown to do what
Recognize certain cytosolic bacterial antigens with HLA class I to kill infected cell
67
Many obligate intracellular pathogens drive the immune response towards a _____ type of response
Th2 (antibody producing)
68
Why do obligate intracellular pathogens encourage Th2 responses
To down-regulate the Th1 responses
69
Th1 responses are good at killing what pathogens
Intracellular pathogens
70
Another mechanism used by intracellular pathogens to evade the immune response is to become _______ within the host cell – in effect, “hiding” intracellularly until the immune response wanes and it is safe for them to renew active growth
Latent
71
Strong CD4+ Th1 cell responses correlate with protective immunity against what
Fungi
72
During intracellular bacterial infections ____ are important early on, while ____ are important later in the response. 1. CD8+ T cells –CD4+ T cell 2. NK cells –CD8+ T cells 3. NK cells –γdelta T cells 4. γdelta T cells –NK cells
2. NK cells –CD8+ T cells
73
What immune responses are good at killing fungi
Innate & adaptive
74
What does the innate immune responses include
Neutrophil phagocytosis (PRR recognize fungal PAMPS), complement (MBL pathway)
75
What does the adaptive immune responses include
-Th1-mediated responses important for controlling opportunistic fungal infections -IFN-γ is necessary for increasing phagocytic activity -Th17 are also involved in controlling fungi
76
What are the phases of virally infected cells
Extracellular & intracellular
77
Viruses are considered
Obligate intracellular pathogens
78
Viruses are processed _____ and ________
Endogenously (HLA class 1), exogenously (HLA class 2) on APCs
79
Where else can viral antigens be found
Unprocessed in the host cell membrane
80
Humoral immunity to viral infections- 4 responses of antibodies
-Antibody can neutralize viral attachment -Opsonization of virus or host cells expressing viral antigens in their surface (enhance phagocytosis by neutrophils & macrophages) -Activating complement to destroy enveloped viral particles via classical pathway -ADCC of infected host cells
81
Antibodies can help only when the virus is
Outside the host cell
82
Cellular immunity against intracellular virus particles: Early (innate)
NK cells sense lack of self via lack of self
83
Cellular immunity against intracellular virus particles: late (adaptive phase)
CTL (Cytotoxic t cell specific for HLA class 1), induction of antiviral state by interferons (IFNα/β by all nucleated cells) or IFNγ (Th1, CTL, γdelta TCR+ cells, NK cells)
84
Do interferons directly kill viruses
NO
85
What are the functions of interferons on viral infections
-Decrease in membrane fluidity, preventing viral penetration and release from the host cell -Production of enzymes which destroy viral nucleic acids -Inhibition of viral protein synthesis -Upregulation of HLA expression on the host cell surface -KNOWN AS ANTIVIRAL STATE
86
What is the viral response to our defense
Block IFN (hepatitis), block HLA (herpes, adenoviruses), block complement activation (influenza A), antigenic variation (rapid mutations- influenza), production of homologues of immune regulatory cytokines (IL-10 produced by EBV)
87
Innate- cellular response
NK cells- kills virus infected host cells, produces type 2 interferons Infected host cell- Produces type 1 interferons that induce antiviral state
88
Adaptive- humoral response
IgG, IgM, IgA antibodies- blocks virus binding to host cell receptors IgG, IgM antibodies- Enhances phagocytosis of virus particles (IgG) and activates complement pathway (IgG/ IgM)
89
Adaptive- cellular response
IFNγ secreted by CD4+ Th1 (type 2 interferons)- induces antiviral state in host cells CD8+ CTLs- Kill virus-infected host cells Killer cells/ antibody- ADCC
90
Immunity to protozoan parasites (unicellular organisms):
Extracellular protozoan parasites: Ab (Th2 dominant responses) Intracellular protozoan parasites: CMI (Th1 dominant responses)
91
Immune Responses to Helminthic Parasites
*IgE antibody responses (Th2 dominant responses) *Eosinophils
92
Septic syndrome and SIRS – mediated by ______
Massive release of proinflammatory cytokines
93
A hallmark of helminthic parasite infections in humans is the production of _____
IgE
94
Another hallmark of helminth infections is ____
Eosinophilia (abnormally high level of eosinophils in the circulation) which interact with IgE to produce the allergy symptoms.
95
Large amount of what 4 things can cause septic syndrome & SIRS
-LPS- gram negative bacteria (engage PAMPS) -Peptidoglycan, teichoic acid- gram positive bacteria (engage PAMPS) -F-met-leu-phe 5'- mCPG DNA (engage PAMPS) -Viral or bacterial superantigens
96
Your patient is found to have a deficiency in IFN-γ production. Infections with which of the following agents are most like to be exacerbated in this patient? A. Parasitic helminths B. Encapsulated bacteria C. Viruses and other intracellular pathogens D. Toxin elaborating bacteria
C. Viruses and other intracellular pathogens
97
Type 1 interferons exert their antiviral effects by which of the following mechanisms? A. Increasing membrane fluidity B. Increasing endogenous antigen processing pathways C. Increasing viral protein synthesis to increase presentation
B. Increasing endogenous antigen processing pathways
98
The host response to parasitic helminth infestations is most similar to which of the following? A. Allergies and allergic asthma B. Sepsis or the systemic inflammatory response syndrome (SIRS) C. Type 1 hereditary angioedema D. Toxic shock syndrome E. Responses to viral infections
A. Allergies and allergic asthma

Immunology (3 decks)

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