T helper cell-dependent induction of resting B cell differentiation need not require cognate cell interactions.
We have analyzed the role of cognate interaction with helper T cells (Th) in support of resting B cell differentiation to plaque formation. Co-culture of histoincompatible resting B cells and resting Th cells resulted in the induction of plaque-forming cells when dimeric but not monomeric fragments of anti-T cell receptor (TcR) antibody were added to culture. The efficiency of B cell activation was comparable to that supported by lipopolysaccharide and lectin-mediated Th-B cell conjugate formation. Further, if resting Th cells were preactivated with antigen and histocompatible antigen-presenting cells, the requirement for addition of anti-TcR to mixtures of histoincompatible Th and B cells was obviated. These results demonstrate that TcR-mediated Th recognition of major histoincompatibility complex class II/antigen composites on the resting B cell membrane does not provide obligate signals for B cell differentiation to plaque formation. We are left with two possibilities. Either the entire process of Th cell-dependent induction of resting B cell differentiation is mediated by soluble lymphokines or if Th-B cell contact is mandatory, it is mediated through nonpolymorphic cell surface determinants.
Julius
M H
MH
Department of Immunology, McGill University, Montreal, Basel Institute for Immunology, Quebec, Canada.
Rammensee
H G
HG
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000917:Antibody Formation; D001402:B-Lymphocytes / Q000276:immunology*; D002454:Cell Differentiation; D002460:Cell Line; D005260:Female; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D008211:Lymphocyte Cooperation; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D011948:Receptors, Antigen, T-Cell / Q000276:immunology / Q000502:physiology; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*
D000911:Antibodies, Monoclonal; D000949:Histocompatibility Antigens Class II; D011948:Receptors, Antigen, T-Cell