b cell maturation

Question 1

B-1 B cells

Answer 1

• Mostly recognises capsular polysaccharide antigens
  
  • Able to produce IgM without T cell help

Question 2

B-2 B cells

Answer 2

Conventional b cells
○ Marginal zone B cells
○ Follicular B cells
Memory B cells

Question 3

Spleen structure

Answer 3

t cell zone on the inside of the white pulp, follicles on the outside, then red pulp on the very outside

Question 4

initiation of the follicle

Answer 4

• B cells reside in follicles due to expression of CXCR5 attracted to CXCL13
• Following activation, B cells upregulate CCR7 to move towards the paracortex
  T cell zone, high in CXCL11/12
  interaction between TFH cells and b cells promotes TFH differentiation further

Question 5

activation of b cells

Answer 5

subcapsular macrophages can give antigen (not degraded) to FDCs

Question 6

follicular dendritic cells

Answer 6

stromal cell that can present antigen
Antigen stays in place because of opsonisation (held by CCR1 and Fc receptor)

Question 7

marginal zone b cells

Answer 7

• Marginal zone = border between red and white pulp
  
  • Make rapid responses to blood-borne antigens
    ○ Have a lot of contact with antigen
  • Relatively broad specificity
  • Usually t cell independent responses and does not generate memory

Question 8

follicular b cells

Answer 8

• Reside in the follicle
  
  • Majority of b cells
  • Co-expression of IgG and IgM
  • Capable of recirculating through lymphoid tissues
  • Higher activation threshold for proliferation and differentiation

Question 9

memory b cells

Answer 9

• Not fully differentiated - can define their antibody affinity multiple times
  ○ Can be created at many different times throughout B cell response
  ○ Allows them to respond to variations in original pathogen upon re-infection
  Rapid response to re-encounters