title: Involvement of I-A-restricted B-B cell interaction in the polyclonal B cell differentiation induced by lipopolysaccharide.
abstract: The present study has examined a functional role of Ia molecules expressed on murine B cells in polyclonal B cell differentiation induced by lipopolysaccharide (LPS). Reverse, IgM PFC responses of unprimed B cells induced by LPS in the apparent absence of T cells and adherent accessory cells were markedly inhibited in a haplotype-specific manner by Fab monomer fragment of anti-class II (Ia) but not anti-class I MHC monoclonal antibody (mAb). However, the degree of inhibition of LPS responses of H-2-heterozygous F1 B cells expressing both parental I-A products by either one of anti-I-A mAb was at best half that of the parental B cells. Interestingly, when (B10 x B10.-BR)F1 (H-2b/k) B cells were fractionated into adherent and nonadherent populations by their ability to bind to parental B10 B cell monolayers, LPS responses of F1 B cells adherent to and nonadherent to the B10 B cell monolayers were selectively inhibited by anti-I-Ab and anti-I-Ak mAb, respectively. These results suggest that LPS-responsive F1 B cells comprise at least two separate populations with restriction specificity for only one of the parental I-A products expressed on B cells. In addition, it was demonstrated that the I-A-restriction specificity of LPS-responsive B cells is "plastic" and determined by H-2-genotype of bone marrow cells present during B cell ontogeny but not by that of radiation-resistant host elements. Namely, the LPS responses of B10-derived B cells from (B10 + B10.BR) (H-2b x H - 2k)F1 radiation bone marrow chimeras but not from B10 (H-2b x H-2k)F1 chimeras became sensitive to the inhibition of anti-I-Ak mAb in the presence of mitomycin C-treated I-Ak-positive B cells, supporting a notion of receptor-Ia molecules interactions rather than like-like interactions. Thus, the present results provide evidence indicating that B-B cell interaction via recognition of self-I-A products is a crucial event in the polyclonal B cell differentiation induced by LPS.
authors.affiliation: Division of Oncogenesis, Osaka University Medical School, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Takahama
authors.forename: S
authors.initials: S
authors.lastname: Ono
authors.forename: K
authors.initials: K
authors.lastname: Ishihara
authors.forename: M
authors.initials: M
authors.lastname: Muramatsu
authors.forename: T
authors.initials: T
authors.lastname: Hamaoka
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D001402:B-Lymphocytes / Q000187:drug effects / Q000276:immunology*; D001853:Bone Marrow / Q000528:radiation effects; D001854:Bone Marrow Cells; D002454:Cell Differentiation; D002478:Cells, Cultured; D004755:Enterobacteriaceae / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D007075:Immunoglobulin M / Q000276:immunology; D008070:Lipopolysaccharides / Q000276:immunology / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D011828:Radiation Chimera
chemical_list: D000911:Antibodies, Monoclonal; D000949:Histocompatibility Antigens Class II; D007075:Immunoglobulin M; D008070:Lipopolysaccharides