Ligation of CD5 on resting B cells, but not on resting T cells, results in apoptosis.
The CD5 molecule is expressed by a B cell subset. We have demonstrated that resting B cells do not proliferate in response to CD5 ligation, whereas cells preactivated with anti-IgM and IL-2 do so. Here, we specifically studied the effects of anti-CD5 and anti-IgM on apoptosis of CD5+ B cells. Both ligation of CD5 or of surface IgM (sIgM) resulted in apoptosis. This started earlier following ligation of CD5 than with sIgM, and both responses were time dependent. CD5-induced apoptosis was independent of the epitope recognized or the way the antibody was presented to the B cells. CD5+ B cells were more sensitive to IgM-induced apoptosis than CD5 B cells. Engagement of CD5 or CD3 expressed by T cells failed to induce apoptosis. Our data indicate differences in the function of CD5 molecules on tonsillar B cells, compared with blood T cells and suggest that cross-linking CD5 on B cell activates specific pathways responsible for apoptosis.
Pers
J O
JO
Laboratory of Immunology, Brest University Medical School, France.
Jamin
C
C
Le Corre
R
R
Lydyard
P M
PM
Youinou
P
P
D017209:Apoptosis / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology* / Q000473:pathology; D018956:CD5 Antigens / Q000276:immunology*; D002478:Cells, Cultured; D006801:Humans; D008024:Ligands; D013601:T-Lymphocytes / Q000276:immunology* / Q000473:pathology
D018956:CD5 Antigens; D008024:Ligands