title: The role of interleukin 1 in human B cell activation: inhibition of B cell proliferation and the generation of immunoglobulin-secreting cells by an antibody against human leukocytic pyrogen.
abstract: The role of factors released by monocytes (M phi) in the activation of human B lymphocytes was examined by studying the effect of an antiserum against human leukocytic pyrogen (LP) on mitogen-stimulated B cell proliferation and the generation of immunoglobulin-secreting cells (ISC) by peripheral blood mononuclear cells (PBM). Antiserum against LP was obtained from rabbits immunized with LP-containing human M phi supernatants. The globulin fraction of this antiserum inhibited pokeweed mitogen- (PWM) stimulated B cell proliferation and the generation of ISC in a concentration-dependent manner, with 50% inhibition of responsiveness observed with 10 micrograms/ml. By contrast, PWM-induced T cell [3H]thymidine incorporation was not inhibited by concentrations of anti-LP as great as 2000 micrograms/ml. The F(ab')2 fraction of anti-LP also inhibited the generation of ISC in response to both PWM and formalinized Staphylococcus aureus, but required 50 micrograms/ml to achieve 50% inhibition. Anti-LP inhibited the generation of ISC only if present during the first 24 hr of a 6 to 7-day incubation; later addition was not inhibitory. Inhibition was more marked in cultures partially depleted of M phi than in whole PBM cultures. Whereas absorption of the anti-LP with PBM failed to remove the capacity to inhibit the generation of ISC, anti-LP-mediated inhibition of responsiveness could be reversed by the addition of crude M phi culture supernatants or a variety of highly purified interleukin 1 (IL 1) preparations, but not by T cell supernatants. These results indicate anti-LP inhibits human B cell activation by removing the requisite M phi-derived factor IL 1 and also confirm that IL 1 plays an essential role in B cell proliferation and the generation of ISC in man.
mesh_terms: D000818:Animals; D000921:Antibody-Producing Cells / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D001666:Binding Sites, Antibody; D006801:Humans; D007106:Immune Sera / Q000494:pharmacology; D007108:Immune Tolerance; D007375:Interleukin-1 / Q000502:physiology*; D008213:Lymphocyte Activation; D008262:Macrophage Activation; D011043:Pokeweed Mitogens / Q000494:pharmacology; D011506:Proteins / Q000276:immunology*; D011817:Rabbits; D013211:Staphylococcus aureus / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology
chemical_list: D007106:Immune Sera; D007375:Interleukin-1; D011043:Pokeweed Mitogens; D011506:Proteins; C008270:leukocyte endogenous mediator