Memory B cells from human tonsils colonize mucosal epithelium and directly present antigen to T cells by rapid up-regulation of B7-1 and B7-2.
Human memory B cells that carry mutated IgV region genes were isolated from tonsils by negative selection of IgD+ naive B cells and CD38+ germinal center B cells and plasma cells. They were mainly found within the intraepithelial areas, but not in the B cell follicles of human tonsils. Memory B cells but not naive B cells have the capacity to present antigen directly to T cells, owing to the constitutive expression of the accessory molecules B7-1/CD80 and B7-2/CD86. Signals through antigen receptors and CD40 antigen result in these two molecules being further up-regulated more rapidly and strongly on memory B cells than on naive B cells. The unique anatomical localization of memory B cells beneath the surface of mucosa, together with their strong APC capacity, may explain the well-known prompt and robust secondary antibody responses.
Liu
Y J
YJ
Schering-Plough, Laboratory for Immunological Research, Dardilly, France.
Barthélémy
C
C
de Bouteiller
O
O
Arpin
C
C
Durand
I
I
Banchereau
J
J
D000938:Antigen-Presenting Cells / Q000276:immunology*; D015703:Antigens, CD; D000954:Antigens, Surface / Q000276:immunology; D016175:B-Lymphocyte Subsets / Q000276:immunology*; D018122:B7-1 Antigen / Q000096:biosynthesis / Q000276:immunology*; D051940:B7-2 Antigen; D023201:CD40 Ligand; D002478:Cells, Cultured; D005455:Fluorescent Antibody Technique; D006801:Humans; D007156:Immunologic Memory / Q000276:immunology*; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000276:immunology*; D009092:Mucous Membrane / Q000276:immunology; D014066:Palatine Tonsil / Q000166:cytology; D015854:Up-Regulation / Q000276:immunology
D015703:Antigens, CD; D000954:Antigens, Surface; D018122:B7-1 Antigen; D051940:B7-2 Antigen; C497964:CD86 protein, human; D008562:Membrane Glycoproteins; D023201:CD40 Ligand