Lecture 27- Adaptive Immunity Flashcards

1
Q

Adaptive Immunity

A

Specific immune response- specific to each pathogen
Several days to mobilize (innate immunity is faster)

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2
Q

Lymphocytes

A

Types of white blood cells, originate in marrow
2 types involved in adaptive immunity
B cells- mature in marrow
T cells- mature in thymus

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3
Q

Where do B cells mature?

A

Bone marrow

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4
Q

Where do T cells mature?

A

Thymus

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5
Q

Antigen (Ag)

A

Any foreign substance that elicits B or T cell response
Mostly proteins or polysaccharides on foreign organism
Epitope: Specific region exposed on surface of Ag
Specifically binds Ag receptor of B or T cell

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6
Q

Epitope

A

Specific region exposed on surface of Ag
Specifically binds Ag receptor of B or T cell

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7
Q

Self-Tolerance (Adaptive Immunity)

A

Depends on ability to distinguish self from non-self
Possible b/c individuals are biochemically unique

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8
Q

B and T cell Diversity

A

Many different B and T cell Ag receptors are generated via genetic recombination and deletion when cells are activated. SPECIFIC

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9
Q

Proliferation of B and T Cells

A

Once activated, multiple cell divisions-> many identical cells

Can become…
Effector cells
Memory cells

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10
Q

What are effector cells?

A

Short lived, work immediately against Ag, any pathogen producing Ag
- Plasma cells, helper T cells, cytotoxic T cells

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11
Q

What are memory cells?

A

Long lived, ready to divide if Ag reappears

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12
Q

Clonal Selection

A

Cell proliferation based on use

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13
Q

Immunological Memory

A

Long-term protection, result of prior infections

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14
Q

Primary Immune Response

A

Response to 1st exposure to Ag

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15
Q

Secondary Immune Response

A

Exposed to same Ag, respond faster- 2-7 days
Stronger, more prolonged

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16
Q

B cells and T cells are types of what?

A

Lymphocytes

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17
Q

B cells components

A

Membranes contain Y-shaped receptors
4 polypeptides
2 heavy chains
2 light chains
Constant (C) region
Variable (V) region

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18
Q

B cell Activation

A

No pathogen- inactive
Ag binds receptor
-> Cells secrete soluble form
= Antibody (Ab)
= Immunoglobulin (Ig)

19
Q

T Cells Overview

A

Also have Ag receptors with 2 parts
Alpha and Beta chains
V and C regions

20
Q

T cell Ag Receptors

A

Only bind Ag fragments on surface of host cell
Ag fragments displayed by
- Pathogen-detecting cells
- Infected cells

21
Q

What are the 2 general responses in adaptive immunity?

A

Humoral Response and Cell-mediated Response

22
Q

Humoral Response

A

Via antibodies in blood, lymph (B cells)

23
Q

Cell-mediated Response

A

Infected host cells destroyed by specialized T cells (cytotoxic T cells)

24
Q

Antigen Presenting Cell (APC)

A

Can be infected or specialized for detection
Presents antigen fragment

25
Q

Helper T Cells

A

T cell with specific receptor bind APC Ag fragment
-> T cell activated via cytokines
Autocrine and paracrine signals
Positive feedback

26
Q

Once active, helper T cells activate…

A

B cells- Humoral immunity
Cytotoxic T cells- Cell-mediated immunity

27
Q

Cytotoxic T cells

A

Cell-mediated response
Use toxic proteins to kill infected cells before pathogens mature
Activated by…
- Signals from helper T cells
- Interactions with APC- bind Ag fragment

28
Q

Activated Cytotoxic T cells release what?

A

Perforin: Forms pores
Granzymes: Initiate apoptosis
-> Infected cell dies, T cell moves on

29
Q

B cells & Antibodies

A

Humoral response
B cell activated by helper T cell
Produces Memory B cells and plasma cells
Plasma cells secrete antibodies

30
Q

Antibody Functions

A

DO NOT kill pathogen directly
3 mechanisms
- Neutralization
- Opsonization
- Complement System

31
Q

Neutralization

A

One function of antibody- Binds virus, interferes with activity

32
Q

Opsonization

A

One function of antibody- Binds bacteria, promotes phagocytosis

33
Q

Complement System

A

One function of antibody- Antibody binds Ag on foreign cell
Complement protein binds Ab-Ag complex
Produces membrane attack complex- pores in PM
Water, ions rush in-> lysis

34
Q

Vaccines

A

Harmless variant or derivative of a pathogen that stimulates adaptive immune response

35
Q

How do vaccines work?

A

Stimulate primary immune response
Pathogen triggers secondary response-> No illness

36
Q

Live attenuated vaccine

A

Live but weakened, avirulent form of pathogen (cannot cause sickness)

37
Q

Inactivated vaccine

A

Whole pathogen, killed (by heat or chemicals)

38
Q

Subunit vaccine

A

Only part of pathogen (antigen containing epitope)

39
Q

DNA/mRNA

A

DNA/mRNA containing gene for antigen, expressed within vaccinated individual

40
Q

Antigenic Drift

A

Small changes in viral antigens due to mutation

41
Q

Antigenic Shift

A

Major changes in vial antigens due to reassortment/recombination

42
Q

Strain Replacement

A

Replacement of a common strain with a less common one
Often due to successful vaccination against common strain

43
Q

Herd Immunity

A

Vaccinate enough of population so that disease cannot spread
R: Transmission rate
Goal: R<1
Infected individual transmits to <1 person on average
Protects unvaccinated

44
Q

Sequence the activation of the adaptive immune response.

A
  1. APC operates
  2. Helper T cells detect antigen
  3. B cells activated
  4. Antibodies released
  5. Reinfection triggers secondary response