Unit 2 - Adaptive Immune System Flashcards by Sam Myers

Adaptive Immune system has _____ and _____.

specificity

memory

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What are the two types of adaptive immunity?

1) Antibody-mediated (B-cell)

2) Cell-mediated (T-cell)

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______ = antibody generator

antigen

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Define antigen

Any molecule that reacts specifically with Ab or Ag receptor on lymphocyte
**Doesn’t necessarily induce IR

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Define immunogen

Antigen that can induce IR

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_______________ = relative ability of AG to elicit IR

antigenic/immunogenic

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Antigenic determinant = ______

epitopes

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What are epitopes?

part of antigen that the antibody recognizes and binds to

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_____ = main immune cell

Antibody

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Antibodies are produced by ______

B-cells (B-lymphocytes)

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Where are antibodies developed?

bursa of bird, bone marrow of humans

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Antibodies are __-shaped

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Some B cells form ____ cells

memory

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Describe the Antibody structure

Y-shaped
top of Y = Fab region (2 identical arms)
bottom of Y = Fc region (1 stem)

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Antibody structure:

Arms bind to ??

specific antigen

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Antibody structure:

What does the stem do?

tags antigen for destruction by other immune system components

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Antibody structure:

Antibodies have a ____ and a ____ chain

light and heavy

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Antibody structure:

2 types of light chains

lambda
kappa
*both light chains are identical

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Antibody structure:

5 types of heavy chains

IgM = mu
IgG = gamma
IgA = alpha
IgD = delta
IgE = epsilon

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Types of antibodies:
\_\_\_\_:
-can cross placenta
-makes up 75% of immunoglobulins
-most prevalent
-secondary response
-opsonization (enhances phagocytosis)
-neutralizes viruses and toxins

IgG

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Types of antibodies:
____:
-monomeric when attached to B cell surface as a receptor
-pentameric in serum, 5 monomers held together by a J chain
-primary response

IgM

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Types of antibodies:
____:
-unknown function
-monomeric form
-found in serum and on B cell surface as receptor
-very low amounts
-may be backup in case IgG not functioning

IgD

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Types of antibodies:
____:
-primary antibody produced by cells of the mucous membranes
-low amount and monomeric form in serum
-dimeric in secretions (more stable in dimeric form)
-neutralizes bacteria and viruses by preventing them from attacking to mucous membranes
-passive immunity for baby from mom (FOUND IN BREAST MILK)

IgA

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Types of antibodies:
____:
-found in mast cells and basophils
-low levels in serum
-Ag receptors on mast cells (tissues) and basophils (blood)
-functions include anaphylactic and hypersensitivity

IgE

Give a super quick summary of the Antibody types

IgG - crosses placenta, opsonization, secondary response IgM - primary response, strongest in serum IgD - unknown function IgA - mucous membranes, crosses breast milk, strongest in secretions IgE - mast cells and basophils

Describe antibody-mediated (humoral) immunity

- When Ab binds to Ag, C1 is activated - C1 is then converted to C1qrs - C1qrs converts C4 to C4b - C4b combines with C2 to make C4b2 - C1qrs convers C4b2 to C4b2a C4b2a = C3 convertase -alternative pathway commences ``` Alternative pathway: C3b + C3 convertase act on C5 to produce C5a and C5b C5b combines with C6, C7, C8, and C9 -forms the MAC complex -pore formation leads to cell lysis ```

What is worse? | C1 deficiency or C3 deficiency

C3 deficiency

What does Antibody-mediated (humoral) immunity do? (2)

1) Activates phagocytic cells | 2) Neutralization

Cell-mediated immunity controlled by ______

T-cells

Where do T-cells mature?

thymus

T-cells do not recognize free Ag, how do they recognize them?

The Ag must be presented by one of the body's own cells in order to recognize it.

What acts as an antigen-presenting cell?

MHC molecules

What are the two types of T-cells?

1) cytotoxic T cells | 2) helper T cells

Tc cells with CD_

CD8

Th cells with CD_

CD4

Tc cells with MHC Class _

Th cells with MHC Class _

What do cytotoxic T cells do?

- differentiate into Tc which destroy infected or cancerous cells - CD8 - recognize Ag presented by MHC Class 1 molecules

What do helper T cells do?

- differentiate into Th which activate B cells and macrophages - CD4 - recognize antigens presented by MHC Class 2 molecules ``` Th1 = activate macrophages Th2 = activate B cells ```

Describe Antibody-Dependent Cellular Toxicity (ADCC)

- Effector cells bind through their surface receptors to Ab molecules coating the target cells - Activation of effector cells - Release of material damaging targets - Macrophages - Eosinophils - NK cells

Purpose of the lymphoid system?

Tissues & organs designed to bring B and T cells into contact with Antigens that enter the body

Lymphatic vessels carry fluid called ____

lymph

Primary lymphoid organs?

bone marrow thymus * both B and T cells are produced in bone marrow * B cells mature in bone marrow * T cells mature in thymus Once mature, lymphocytes gather in secondary lymphoid organs waiting to encounter Ag

Secondary lymphoid organs?

Site where lymphocytes gather to collect Ags - lymph nodes - spleen - tonsils - adenoids - appendix * Lymph nodes capture Ags from lymph * Spleen capture Ags from blood

What is MALT?

MALT = mucosal-associated lymphoid tissue | -plays key role in adaptive IR that prevents microbes from invading mucosal surface

What is SALT?

SALT = skin-associated lymphoid tissue | -prevents microbes from invading skin

clonal selection

Only B-cells capable of making correct Ab bind to Ag

What is clonal selection done by?

B-cells

clonal expansion

cells that bind Ag begin dividing, produce population of clones

Somatic mutations for further _______

selection *this is only in B cells, not T cells

What cells are T memory cells

CD45RO

What cells are B memory cells

CD27 and surface IgG, IgA or IgE

List 3 points about memory cells

- More readily stimulated by an antigen - Greater combining power - Basis for the principle of vaccination

What is the difference between Type 1 and Type 2 T-independent antigens

Type 1: - T-independent antigens are polyclonal activators - stimulate a wide variety of B cells independently of their specific antigen receptors Type 2: - T-independent antigens with repeating determinants cross-link Ig receptors - Give rise to low-affinity IgM rather than IgG Ab response and do not induce memory response

What are cytokines and what do they do?

- soluble intercellular communication factors (hormones of the immune system) - non-antigen specific molecules - diverse activity * Important role in protection against infectious diseases - contribute to the control of infection - contribute to the development of pathology

An interferon is a type of ______

cytokines

What is an interferon?

molecule secreted by virus-infected cells that interferes with viral replication in bystander cells

___ down regulates Th1 cells

IL-4

____ suppresses the activity of Th2 lymphocytes

IFNy