title: Anti-HLA-class II monoclonal antibodies inhibit polyclonal B cell differentiation in vitro at the accessory cell level.
abstract: We produced and characterized a panel of anti-HLA class II monoclonal antibodies (mAb) to study the inhibition of T cell-dependent B cell differentiation. The newly produced mAb belonged to different isotypes and subclasses, and recognized at least two different nonpolymorphic HLA class II determinants. We found that anti-HLA class II mAb inhibited the pokeweed mitogen (PWM)- and interleukin 2-driven T cell-dependent IgM synthesis, but did not affect the phorbol myristate acetate-, phytohemagglutinin-, anti-T3- or PWM-induced T cell proliferation. Moreover, when the mAb were tested in a monocyte-independent B cell differentiation assay in which T cells are activated by insoluble anti-T3 mAb in the absence of accessory cells, no effect was seen on IgM synthesis. These data indicate that inhibition of T cell-dependent B cell differentiation by anti-HLA class II mAb is caused by interference with an accessory cell function essential for B cell differentiation.
mesh_terms: D000911:Antibodies, Monoclonal / Q000008:administration & dosage / Q000276:immunology* / Q000302:isolation & purification; D000918:Antibody Specificity; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology*; D002454:Cell Differentiation / Q000187:drug effects*; D002478:Cells, Cultured; D006681:HLA-D Antigens / Q000276:immunology*; D006801:Humans; D007075:Immunoglobulin M / Q000096:biosynthesis; D007376:Interleukin-2 / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000187:drug effects; D008211:Lymphocyte Cooperation / Q000187:drug effects; D009000:Monocytes / Q000276:immunology; D011043:Pokeweed Mitogens / Q000494:pharmacology
chemical_list: D000911:Antibodies, Monoclonal; D006681:HLA-D Antigens; D007075:Immunoglobulin M; D007376:Interleukin-2; D011043:Pokeweed Mitogens