Flashcards in Adaptive Immunity: B cells Deck (39):
Most common Ab
Heavy chain is recombination of ____ segments
V, D, J
Light chain is recombination of ____ segments
Has 4 constant regions per H chain
Found mainly in blood
Secreted as monomer
Secreted as dimer
Secreted as pentamer
IgE found most where?
Tissue bound to mast cells
Ab in transplacental transfer
Agglutination protects against ___
Neutralization protects agains ____
viral infection , bacterial exotoxins and endotoxins
NK cells express ____ Fc receptors
Pro-B cell stage
VDJ recombination at heavy chain loci
Pre-B ell stage
VJ recombination at light chain loci
Surrogate light chain complex
Made by Pre-B cells (Vpre B and lambda 5 proteins)
pre-B cell complex
= surrogate light chain complex + u heavy chain protein
What do both B1 and B2 B cells express?
CD19, CD20, IgM, IgD
Levels of IgM and IgD on B1?
High IgM, low IgD
Levels of IgM and IgD on MZ B cells?
High IgM, low IgD
Levels of IgM and IgD on follicular B cells?
High IgD, low IgM
B1 B cells are enriched in ____
serosal lined cavities: pleural and peritoneal cavities
B1 B cell function:
Spontaneously differentiate into plasma cells
Secrete IgM abs w/o stimulation
Where are MZ B cells found?
When do MZ B cells respond?
During T cell-independent (TI) responses
Where are follicular B cells found?
Secondary lymphoid organs: Spleen, Lymph nodes, MALT
Most numerous B cell subset?
Follicular B cells
When do follicular B cells respond?
During T cell-dependent (TD) responses and germinal center reaction
Function of follicular B cells?
Source of high affinity, switched Abs
Give rise to memory B cells and long term plasma cells
Secreted by follicular dendritic cells to direct B cells to follicles
Receptor to CXCL13 on B cells to direct them to follicles
Secreted by reticular cells to direct T cells to T cell zones
Receptor to CCL19, CCL21 on T cells to direct T cells towards T cell zones
Adapter molecules that connect surface Ig to intercellular signaling pathways
CD19, CD21, CD81
Co-receptor molecules in signal 1 of B cell activation
Amplify CD79a/b induced signals
What Ab is primarily secreted during TI response?
Expressed on activated CD4+ T follicular helper cell which binds to CD40 on B cell during cognate interaction in TD response
Expressed on activated B cell that binds to CD154 on activated CD4+ T follicular helper cell during cognate interaction in TD response