title: T-dependent activation of resting B cells mediated by concanavalin A.
abstract: In cultures containing long-term cultured lines of antigen-specific helper T (Th) cells, normal unprimed B cells and concanavalin A (Con A), induction of B cells to immunoglobulin secretion and DNA synthesis was observed. The plaque-forming cell (PFC) response was large (frequently greater than 75 000 PFC/10(6) input B cells) demonstrating the polyspecific nature of the response. Con A-mediated maturation and induction to DNA synthesis of responding B cells was completely Th cell dependent and inhibited with methyl-alpha-D-mannoside. Both resting and blasted B cells, separated by Percoll density centrifugation, were induced to DNA synthesis and immunoglobulin secretion. Responses were completely unrestricted by the B cell major histocompatibility complex, even at the level of the resting B cell. The polyclonal nature of the response taken together with the Con A-mediated bypassing of T cell specificity and restricting haplotype indicates that this response is analogous to lectin-mediated cytotoxicity.
mesh_terms: D000818:Animals; D000921:Antibody-Producing Cells / Q000276:immunology; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology*; D003208:Concanavalin A / Q000494:pharmacology*; D004247:DNA / Q000096:biosynthesis; D007399:Interphase; D008213:Lymphocyte Activation / Q000187:drug effects; D008211:Lymphocyte Cooperation / Q000187:drug effects; D008766:Methylmannosides / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*
chemical_list: D008766:Methylmannosides; D003208:Concanavalin A; C008466:methylmannoside; D004247:DNA