B cell immunity

Question 1

What can B cells do that T cells cant

Answer 1

attack EC, attack immediately and can be passed down

Question 2

Structure of a B cell

Answer 2

Variable and Constant region ( Y ), blank b cell has IgM and IgD

Question 3

What is CSR

Answer 3

Class switch Recombo - IgM to IgG, IgE or IgA
Happens in the constant region

Question 4

what is SHM

Answer 4

point mutations in the H and L of the variable region
a lot of mutations happen and thus need Tfh help to keep the good ones alive
kept alive by binding to T helper cells

Question 5

B Cell activation

Answer 5

Signal 1 - BCR crowding (multiple antigen binding activates Signal 1 and Endocytosis of antigen - up of anergy
signal 2 - Cd40 bind on T cell CD40L to ensure survival and stop anergy
signal 3 - T CD4 come and differentiate cell

Question 6

Where are b cells located

Answer 6

Primary Follicular

Question 7

when ins IgM secreted and IgG

Answer 7

IgM 3-7 days IgG 7 days plus and stay for a long time

Question 8

what dictates CSR

Answer 8

TH 1 - IFN- gamma for IgG
Gut - TGF-beta for IgA
TH 2 - IL-4 for IgE

Secretion levels of Th cytokines dependent on location of GC

Question 9

Where is IgG located and its strengths

Answer 9

Blood and intestinal tissue
best for opsonization, placenta travel, extravascular diffusion and some neutralization
Major in secondary responses

Question 10

Where is IgA located and its strengths

Answer 10

mucosal lining ( lungs, gut and stomach)
Best for transport across epithelium
most abundant in body (20 serum)

Question 11

Where is IgE located and its strengths

Answer 11

skin and outer lining of stomach lungs and gut
best for mast cell sensitization
none in tissues or fluids

Question 12

Where is IgM located and its strengths

Answer 12

B cells
Best for activation of the complement system
10 binding sites for increase antigen binding

Question 13

IgG levels at Birth?

Answer 13

high until birth then drops off and you are vulnerable
you get more by IgA from breast milk from mom

Question 14

Does the light chain switch in Antbodies

Answer 14

no they do not bc isnt significant but need to maintain 2:1 ration of Kappa to lambda

Question 15

What is linked recognition

Answer 15

B and T cell recognize different parts of same molecule
B can see peptides to haptens and cont and non- cont
T can only see pep 8-12 MHC - I and 12-17 <HC-II and only cont

Question 16

TI response

Answer 16

B cell without T cell CD40 help = just IgM and thus cant create memory cells