Molecular events in B lymphocyte activation: consequences of signals transduced through MHC class II molecules.
Evidence is presented to demonstrate that murine B lymphocytes receive growth stimulatory signals from their surface class II molecules. Monoclonal anti-Ia antibodies enhanced anti-mu-induced B cell proliferative response. The signals through surface immunoglobulin (Ig) and Ia appeared to act sequentially since preexposure to anti-mu was required to observe anti-Ia-induced increase in B cell proliferation. Anti-Ia antibodies did not increase the number of B cells entering the G1 phase of cell cycle but always enhanced transition from G1 into the S phase in response to stimulation with anti-mu. Analysis of early gene expression revealed that signaling through class II molecules led to an increase in anti-mu-induced expression of c-myc, a proto-oncogene, and of ornithine decarboxylase, a key enzyme in polyamine biosynthesis that has been shown to be intimately related to increased cell proliferation.
Baluyut
A R
AR
Department of Microbiology and Immunology, Sanders Brown Center on Aging, Chandler Medical Center, University of Kentucky, Lexington 40536.
Pollok
K E
KE
Bondada
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S
D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D002453:Cell Cycle; D015870:Gene Expression; D016259:Genes, myc; D000949:Histocompatibility Antigens Class II / Q000502:physiology*; D008213:Lymphocyte Activation; D051379:Mice; D008815:Mice, Inbred Strains; D009955:Ornithine Decarboxylase / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D011947:Receptors, Antigen, B-Cell / Q000502:physiology; D011990:Receptors, Transferrin / Q000378:metabolism; D015398:Signal Transduction; D013997:Time Factors
D000949:Histocompatibility Antigens Class II; D012333:RNA, Messenger; D011947:Receptors, Antigen, B-Cell; D011990:Receptors, Transferrin; D009955:Ornithine Decarboxylase