Control of B cell proliferation: inhibition of responses to B cell mitogens induced by plasma cell tumors.
A multitude of factors has been described that positively and negatively regulate B cell proliferation. A model system for the study of negative control of B cell function is provided by mice bearing plasmacytomas (PC-mice). In PC-mice, the primary immune response, as measured by development of antibody-forming cells (AFC), is severely suppressed. The present report specifically identifies a block in B cell proliferation as the apparent cause of this reduction in AFC production. Thus, the proliferative response of B cells from the spleens of PC-mice (PC-spleens) was significantly impaired when stimulated with four different B cell mitogens (lipopolysaccharide, Salmonella typhimurium mitogen, anti-mu conjugated to Sepharose, and 8-mercaptoguanosine). Nevertheless, the mitogen-responsiveness of these B cells was recovered when they were segregated by various methods from macrophages. These data suggest that the proliferative ability of the B cells in PC-spleens is inherently normal. In concordance with this conclusion, it was shown that suppressor cells from PC-spleens can block the proliferation of normal B cells derived from nontumor-bearing mice. This inhibition does not require direct cell contact and is mediated via soluble factors. The relevance of these results to previous studies of PC-induced immunosuppression and to the control of normal B cell proliferation is discussed.
Berman
J E
JE
Zolla-Pazner
S
S
D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D002469:Cell Separation; D003911:Dextrans; D005260:Female; D005434:Flow Cytometry; D006151:Guanosine / Q000031:analogs & derivatives / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008213:Lymphocyte Activation; D008222:Lymphokines / Q000096:biosynthesis / Q000502:physiology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008934:Mitogens / Q000494:pharmacology*; D010954:Plasmacytoma / Q000276:immunology* / Q000378:metabolism; D012486:Salmonella typhimurium / Q000502:physiology; D013154:Spleen / Q000166:cytology / Q000378:metabolism; D013491:Suppressor Factors, Immunologic; D050378:T-Lymphocytes, Regulatory / Q000378:metabolism; D013872:Thionucleosides / Q000494:pharmacology
D003911:Dextrans; D008070:Lipopolysaccharides; D008222:Lymphokines; D008934:Mitogens; D013491:Suppressor Factors, Immunologic; D013872:Thionucleosides; D006151:Guanosine; C025614:sephadex; C037031:8-thioguanosine