Intracellular events associated with inhibition of B cell activation by monoclonal antibodies to HLA class II antigens.
We have investigated several aspects of the inhibitory effects of monoclonal antibodies (mAb) directed against MHC class II antigens in B cell activation/proliferation, using a panel of mAb specifically reactive with antigens encoded by HLA class II loci (DP, DQ, DR). All mAb except the anti-DP mAb inhibited significantly anti-mu plus B cell growth factor-induced DNA synthesis. Only one mAb, however, which was reactive with gene products of all three class II loci (DP, DQ, DR) inhibited anti-mu-induced DNA synthesis as well as c-myc mRNA expression. In addition, the same mAb inhibited the early events induced by anti-mu stimulation alone, including phosphatidylinositol turnover and elevation of [Ca2+]i. In contrast to previous findings in the murine system, none of the anti-MHC class II mAb used in this study increased the cAMP levels.
Holte
H
H
Laboratory for Immunology, Institute for Cancer Research, Oslo, Norway.
Blomhoff
H K
HK
Beiske
K
K
Funderud
S
S
Torjesen
P
P
Gaudernack
G
G
Stokke
T
T
Smeland
E B
EB
D000911:Antibodies, Monoclonal / Q000276:immunology; D000937:Antigen-Antibody Reactions; D001402:B-Lymphocytes / Q000276:immunology*; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D006681:HLA-D Antigens / Q000276:immunology*; D006801:Humans; D066298:In Vitro Techniques; D008213:Lymphocyte Activation; D010716:Phosphatidylinositols / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000235:genetics; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger / Q000235:genetics; D011947:Receptors, Antigen, B-Cell / Q000502:physiology
D000911:Antibodies, Monoclonal; D006681:HLA-D Antigens; D010716:Phosphatidylinositols; D011518:Proto-Oncogene Proteins; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; D011947:Receptors, Antigen, B-Cell; D000242:Cyclic AMP; D002118:Calcium