Adaptive Ag Recognition

Question 1

Components of BCR

Answer 1

surface Ig & 2 invariant chains (Ig alpha, beta)

Question 2

Components of TCR

Answer 2

alpha & beta heterodimer w/ invariant sequence proteins from CD3 complex (sends signal thru zeta)

Question 3

Immune Repertoire

Answer 3

person makes more different forms of Ab than all other proteins put together

Question 4

Allelic Exclusion

Answer 4

gene re-arrangement events that occur w/o Ag (so can build Abs that are specific for 1 Ag)

Question 5

What are the 3 mechanisms for generating lymphocyte receptor diversity?

Answer 5

Combinatorial Diversification
Junctional Diversity
Somatic Hypermutation (for class switching)

Question 6

Combinatorial Diversification

Answer 6

V-J & V-D-J somatic recombinations (requires Rag enzymes)

Question 7

Junctional Diversity

Answer 7

adding nucleotides during process of D-J or V to DJ joining (need TdT)

Question 8

What stage of B cell maturation is the surrogate light chain present?

Answer 8

Pre-B cell

Question 9

What stage of B cell maturation do B cells express Ig?

Answer 9

@ immature B cell stage, express IgM

Question 10

When do B cells express membrane IgM & IgD?

Answer 10

mature, naive B cell

Question 11

What drives B cells from stem cell to pro B cell?

Answer 11

IL-7

Question 12

When do B cells move out to periphery?

Answer 12

when @ immature B cell stage

Question 13

What is purpose of surrogate light chain?

Answer 13

allelic exclusion, B cell will only express 1 of the heavy chains that is coming from 2 alleles

stops rearrange of Ig heavy chain from the 2nd allele

Question 14

When can B cells undergo receptor editing?

Answer 14

when immature B cell, in spleen

Question 15

What is the role of alternative splicing of heavy chain mRNA?

Answer 15

how you get IgM & IgD on B cells, can bring VDJ next to m or d gene

Question 16

What drives stem cell to pro-T cell?

Answer 16

IL-7

Question 17

When do T cells move from cortex to medulla in thymus?

Answer 17

when become double positive T cells (CD4 & 8 on surface)

Question 18

When do T cells express surrogate alpha/beta chain in development?

Answer 18

at pre-T cell stage

Question 19

What is the purpose of surrogate Alpha chain?

Answer 19

allelic exclusion

stops beta chain gene recombo so T cell only expresses 1 of the beta chain alleles

Question 20

When is a T cell an immature T cell?

Answer 20

when it is a single positive (has only CD4 or only CD8)

Question 21

MHC/HLA restriction

Answer 21

ability of T cells to recognize Ags when assoc w/ MHC/HLA haplotype on host cells, provides dual recognition system needed for T cell function (can bind both MHC class I & II)