The changing preference of T and B cells for partners as T-dependent antibody responses develop.
Recirculating virgin CD4+ T cells spend their life migrating between the T zones of secondary lymphoid tissues where they screen the surface of interdigitating dendritic cells. T-cell priming starts when processed peptides or superantigen associated with class II MHC molecules are recognised. Those primed T cells that remain within the lymphoid tissue move to the outer T zone, where they interact with B cells that have taken up and processed antigen. Cognate interaction between these cells initiates immunoglobulin (Ig) class switch-recombination and proliferation of both B and T cells; much of this growth occurs outside the T zones B cells migrate to follicles, where they form germinal centres, and to extrafollicular sites of B-cell growth, where they differentiate into mainly short-lived plasma cells. T cells do not move to the extrafollicular foci, but to the follicles; there they proliferate and are subsequently involved in the selection of B cells that have mutated their Ig variable-region genes. During primary antibody responses T-cell proliferation in follicles produces many times the peak number of T cells found in that site: a substantial proportion of the CD4+ memory T-cell pool may originate from growth in follicles.
MacLennan
I C
IC
Department of Immunology, University of Birmingham Medical School, United Kingdom. i.c.m.maclennan@bham.ac.uk
Gulbranson-Judge
A
A
Toellner
K M
KM
Casamayor-Palleja
M
M
Chan
E
E
Sze
D M
DM
Luther
S A
SA
Orbea
H A
HA
D000818:Animals; D000917:Antibody Formation / Q000276:immunology*; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology*; D002465:Cell Movement; D003713:Dendritic Cells / Q000276:immunology; D006801:Humans; D008213:Lymphocyte Activation; D011947:Receptors, Antigen, B-Cell / Q000276:immunology; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*
D011947:Receptors, Antigen, B-Cell