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B cell activation
B cell activation
B cell activation
Antibody Functions
Antibody functions
100

Where do B cells mature

  • B cell areas of secondary lymphoid tissues 
100

What cell presents antigen to b cells to cause activation

follicular dendritic cells

100

Name the 5 antibody classes

  • IgA, IgG, IgE, IgD, IgM
100

Role of IgD

sensitizes basophils in upper resp.

100

what would happen if someone had an antibody deficiencey 

  • inc susceptibility to extracellular bact. And fungi infections
200

What 3 signals activate thymus dependent B cell

  • Binding antigen 2 b cell
  • Bind complement c3b to B cell
  • TFH cell signals- CD40/CD40L = affinity mat, class switch, etc
200

Explain linked recognition

  • B-cell receptor and the conjugate TFH cell receptor do not recognize the same antigen, but antigen of the same pathogen
200

Describe the role of IgA

extravascular tissues, breast milk, mucosa, neutralization

  • most abundant in body
200

Role of IgM?

first class to be secreted, classical complement pathway


200

Describe immunity in infants under 1 yr

  • susceptible to infxns bc antibodies not built up until 1 yr. Maternal antibodies begin to decline before reaching age of 1
300

How does the requirement of a conjugate T cell for B cell maturation provide a safety net 

unlikely a b cell AND t cell will recognize self antigen and also form a conjugate pair

300

What cell type is in the dark zone of the germinal center and what occurs there

  • centroblasts- proliferation, somatic hypermutation, and class switching
300

Role of IgE?

mast cells, parasites, basophils, eosinophils

300

Define and explain ADCC

  • antibody mediated cytotoxicity- Infected host cells display antigens on surface MHC class I. IgG antibodies bind to their antigen on the host cell surface. Natural killer cells have an Fcγ receptor that binds to the IgG at the host cell surface. Binding to IgG to Fc receptor causes the natural killer cell to destroy the infected host cell.
300

where do b cells find conjugate t cell

boundary region

400

What type of cell is in the light zone and what occurs there?

  • centrocytes- compete for antigen on FDCs, receive survival signals from TFH cells (CD40L and cytokines further somatic hypermutation and selection  plasma cells
400

What determines antibody class

Cytokines

400

Role of IgG?

extravascular tissues, placental transfer, opsonization, neutralization, NK cells in ADCC, complement pathway

  • most abundant in blood
400

Define opsonization

What antibodies opsonize

IgG and IgA (lesser)

400

where is the primary focus formed 

medullary cords

activated b cell becomes either a plasma cell that secrets low affinity IgM or moves back to b cell area

500

review the steps of B cell maturation (include locations)


  • B cell binds antigen > moves 2 boundary region to find t cell conjugate > move to medullary cords >form primary focus>plasma cell (low affinity IgM) OR back B cell area>form germinal center > AID enzyme is activated > somatic hypermutation and class switching
500

Explain the difference in B1 and B2 cells

  • B2- diverse receptors, require T cell, produced in bone marrow, not produced until after birth
  • B1- less diverse receptors, produce antibody in absence of antigen (innate like), no T cell help, renew in periphery, produced in fetus
500

Explain the difference in Thymus dependent and thymus independent response

  • Thymus dependent- requires T cell, high affinity, class swapped antibody made
  • Thymus independent- no T cell needed, primarily secretes low affinity IgM
500

Explain the difference in T1 and T2 responses

  • T1- IDs bact. PAMPs and activate B cells. Quick initial protection
  • T2- IDs repetitive polysaccharides and activates B cells
500

where is the germinal center formed and what happens there

b cell area 

  • AID enzyme is activated > somatic hypermutation and class switching