Humoral immunity (b cell response) dwinell

Question 1

humoral immune responses are an arm of the (adaptive/innate) immune system and is activated by and recognize _, _, _, and _ (which types of molecules)

Answer 1

adaptive

proteins, polysaccarides, lipids, and small chemicals

Question 2

Humoral immunity is mediated by _ lymphocytes and secreted _

Answer 2

B lymphocytes, secreted antibodies

Question 3

When _ molecules recognize antigens, signals are delivered to the lymphocytes by proteins associated w/ the antigen receptors

Answer 3

B cell receptor (BCR) immunoglobulin (Ig) molecules (two or more!)

Iga and Igβ proteins

Question 4

TCR and BCR consist of domains that mediate immune recognition and are different between clones of lymphocytes

Constant (C) region- genetically _

Variable (V) region- genetically _

Answer 4

C, concerved receptor domain

V, variable, diverse antigen recognition domain

Question 5

Variable region of Ig is focused among _

Constant region in the BCR can change but TCR is fixed

Which has a higher affinity for antigen? TCR or BCR?

Answer 5

CDRs

BCR has higher initial affinity, increases during response

TCR affinity is fixed

Question 6

commitment of progenitor cells to develop for B cells-

Answer 6

Heavy chain protein expression

(In T cells it was the TCR Beta chain)

Question 7

_ produced by bome marrow and stromal cells provides the mitogenic signal for developing lymphocytes (B and T) to proliferate

Answer 7

IL7

Question 8

IL7

Answer 8

Lymphocyte precursor proliferation

Question 9

Variable region of heavy chain (IgH) is composed of three gene segments that recombine during cellular differentiation and maturation. They are:

Answer 9

v (variable)

D (diversity)

J(joining)

heavy chain transcript VDJC (also contains constant Cμ) is processed and then expressed at the cell surface

Question 10

B cells are mature (but still naive) in the peripheral immune tissues (follicles) when they express_ and _ on the cell surface

Answer 10

IgM and IgD

Question 11

The BCR is a dimeric protein that confers Antigen Specificity (variable region) and effector function specificity (constant region)

Where would you find the heavy chain, light chain, variable region, constant region, Fab region, and Fc region on a secreted IgG?

Where is the antigen binding site?

Answer 11

Question 12

mechanisms of antigenic diversity

_-variation amongst possible vdj and vj exon combinations

_-removal of nucleotides, addition of nucleotides by TdT enzyme, strand repair during recombination process

Answer 12

Combinatorial, junctional

Question 13

each variable region of the IgH and IgL chain has three regions of hypervariability known as _

Answer 13

CDR (cdr1, cdr2, cdr3)

Question 14

when a naive IgM IgD B cell becomes activated by a helper T cell or another stimuli, it undergoes _ _ and _

Types of B cell outcomes possible include:

Answer 14

clonal expansion

differentiation

Antibody secreting plasma cells, IgG expressing B cells, High-affinity Ig-expressing B cell

Question 15

In the LN follicle, antigens are presented by _ to membrane bound _ on _

Answer 15

follicular dendritic cells (potentially)

IgM, naive B cells

Question 16

Naive b cells require 2 signals for activation

1)

2)

Answer 16

1- bcr binds antigen

2)

a) CR2/CD21 (complement receptor) activated by Cd3 complement protein OR

B) TLR activated by microbial pathogen association molecule (PAMP)

Question 17

Answer 17

Question 18

BCR activation

Answer 18

Two or more BCRs

ITAM: immunoreceptor tyrosibe based activation movif

Activates a battery of transcription factors that drive clonal expansion, differentiation

Question 19

Four b cell responses to antigen after activation-

name 4 things

Answer 19

mitosis, increase cytokine receptors to respond to T cell’s cytokines, migration out of lymphoid follilcles, secretion of IgM

Question 20

if a b cell phagocytoses an antigen, it will present it on Class 2 mhc peptide complex. For the T cell to recognize it, the b cell must express _ and the T cell must express _

Answer 20

B7, cd28

Question 21

T cell-mediated differentiation of activated B cells involves _ ligand from T cell interacting with B cell surface protein _.

Cytokines from T cell also attach to the cytokine receptor on B cell.

Answer 21

Cd40L, CD40

Question 22

B lymphocytes differentiate into antibody secreting _ cells and _ cells

Answer 22

Plasma, memory B

Question 23

in effector b cells, class switching results in antibodies with:

Affinity maturation produces antibody with _

Answer 23

fc regions capable of diverse effector functions

higher affinities for antigen binding (triggered by booster stimulation)

Question 24

B cell differentiation in a secondy exposure causes changes in antibody structure. three changes that can occur:

Answer 24

Affinity maturation (increases affinity)

Switch from membrane to secreted form (change from b cell receptor function to effector function)

Isotype switching (different set of effector functions)

Question 25

isotype switching- antibody mediated mechanisms in host defense

_ activation leading to opsonization and/or microbial killing

_ enhanced by antibody and/or complement components bound to the infectious agent (opsonization)

-_

Answer 25

complement activation

phagocytosis

neutralization

Question 26

different immunoglobulin heavy chains have evolved to carry out different functions. The _ region is inially found of IgM and IgD, but is switched onto other _ regions during the course of the response, hence “isotype switching”

Switching is controlled by _ cells and _

Answer 26

Heavy chain variable (V_H) initially,

Heavy chain constant (C_H)

T helper cells and varying cytokines

Question 27

Define idiotype

Define isotype

Answer 27

Idiotype: shared characteristic between a group of Ig molecules with shared antigen binding specificity and variable region (VH and VL) structure

Isotype: type of antibody as defined by the constant heavy (Ch) region

Question 28

T independent class switching results in Ig_

T dependent? Ig_ and Ig_

Answer 28

M,

G and E

Question 29

The principal effector function of the T-independent production of IgM is _

Answer 29

complement activation

Question 30

T dependent isotype switching.

Helper T cells with CD40L and Cytokines

If there is IFN-y present, make B cells turn into plasma cells that secrete _

If there is IL-4 present, make B cells turn into plasma cells that secrete _

If there are cytokines in mucosal tissues such as TGF-B present, they make B cells turn into plasma cells that secrete _

Answer 30

IgG- Fc receptor-dependent phagocyte responses; complement activation; neonatal immunity (placental transfer)

IgE- immunity against helminths, mast cell degranulation (immediate hypersensitivity)

IgA- Mucosal immunity (transport of IgA through epithelia)