A role for adhesion molecules in contact-dependent T help for B cells.
The role of cell contact in T-dependent B cell activation was examined. Small resting B cells from C57BL/6 mice were cultured with CBA-derived, non-alloreactive cloned T helper cells in anti-T cell receptor V beta 8-coated microwells. This induced polyclonal B cell activation to enter cell cycle (as measured by thymidine incorporation at 2 days) and to secrete immunoglobulin (as measured by an enzyme-linked immunoassay detecting high-rate Ig secretion at 5 days). The inclusion of monoclonal antibodies against LFA-1. ICAM-1 and CD4 in these cultures strongly inhibited antibody responses, although proliferative responses were only inhibited to about 50%. Inhibitory monoclonal antibodies did not significantly affect lipopolysaccharide-induced responses. T cell activation to interleukin (IL) 3 secretion, nor did they inhibit the formation of multicellular clusters containing T and B cells. There was no correlation between the level of expression of adhesion molecules by T cells and their ability to induce B cell responses. Anti-LFA-1 abrogated T-dependent responses to IL2 which were inducible after 2 days in culture, but did not inhibit the induction of this IL2 responsiveness. These results suggest that continued cell contact involving adhesion/accessory molecules induces B cells to proliferate and to respond to T cell lymphokines. A signaling role for cell interaction molecules on B cells is proposed, similar to the role of these and analogous molecules on T cells.
Owens
T
T
Department of Neurology and Neurosurgery, McGill University, Quebec, Canada.
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D015703:Antigens, CD / Q000502:physiology*; D001402:B-Lymphocytes / Q000276:immunology*; D015815:Cell Adhesion Molecules / Q000032:analysis / Q000502:physiology*; D002450:Cell Communication; D005260:Female; D007136:Immunoglobulins / Q000378:metabolism; D018799:Intercellular Adhesion Molecule-1; D008213:Lymphocyte Activation; D016169:Lymphocyte Function-Associated Antigen-1 / Q000032:analysis / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D006377:T-Lymphocytes, Helper-Inducer / Q000502:physiology*
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D015815:Cell Adhesion Molecules; D007136:Immunoglobulins; D016169:Lymphocyte Function-Associated Antigen-1; D018799:Intercellular Adhesion Molecule-1