S. Neron et R. Lemieux, CD5(-CELL-DEPENDENT REGULATION OF THE MURINE T-CELL INDEPENDENT IMMUNE-RESPONSE AGAINST THE HUMAN BLOOD-GROUP-A ANTIGEN() B), Immunological investigations, 26(5-7), 1997, pp. 631-647
The CD5(+)B lymphocyte (B1a) population is known to be involved in mos
t immune responses to microorganism Tl antigens. Moreover, xid mice de
ficient for immune responses against Tl-2 antigens are known to lack t
he B1a population, suggesting a role for B1a cells in Tl-2 immune resp
onses. We previously established that the oligosaccharide human blood
group A antigen stimulated murine Tl-2 immune responses. In this work,
we show that the frequency of anti-A-secreting hybridomas was higher
in mice with larger splenic B1a populations and that in vivo anti-CD5
treatment reduced anti-A immune response without affecting the respons
e against TD RBC antigens. A similar effect was observed by in vitro a
nti-CD5 treatment of splenocytes. The in vivo anti-CD5 treatment also
interfered with the immunization-dependent increase in splenocyte numb
ers. These results are in agreement with an important role for the B-c
ell CD5 receptor in the regulation of Tl-2 immune responses possibly m
ediated by its interaction with the CD72 ligand.