Regulation of malignant B-cell proliferation by direct binding of anti-HLA class-II antibodies.
A panel of five monoclonal antibodies (Mab) and a polyclonal antiserum directed against HLA class II were studied for their effect on growth of mature neoplastic B cells of prolymphocytic origin (B-PLL cells). The polyclonal antiserum and three out of five monoclonal antibodies were able to synergize with phorbol myristate acetate (PMA) to induce proliferation of B-PLL cells of one patient. Cross-blocking experiments showed that the proliferation-inducing Mab recognized closely related epitopes on HLA class-II molecules. The other two monoclonal antibodies recognized different epitopes on HLA class-II molecules and had no effect on proliferation of B-PLL cells. Proliferation induced by the combination of PMA and anti-HLA class-II Mab was inhibited by anti-CD18 (LFA-1) antibodies and was extremely dependent on cell density. This study indicates that certain HLA class II determinants on neoplastic B cells can transduce growth-promoting signals.
Sauerwein
R W
RW
Central Laboratory, Netherlands Red Cross Blood Transfusion Service, Amsterdam.
De Rie
M A
MA
van der Meer
W G
WG
Miedema
F
F
Aarden
L A
LA
D000911:Antibodies, Monoclonal / Q000502:physiology*; D001402:B-Lymphocytes / Q000276:immunology* / Q000473:pathology; D001666:Binding Sites, Antibody; D002455:Cell Division / Q000187:drug effects; D000939:Epitopes / Q000276:immunology; D006681:HLA-D Antigens / Q000276:immunology*; D006801:Humans; D007945:Leukemia, Lymphoid / Q000276:immunology* / Q000473:pathology; D008213:Lymphocyte Activation / Q000187:drug effects; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D000911:Antibodies, Monoclonal; D000939:Epitopes; D006681:HLA-D Antigens; D013755:Tetradecanoylphorbol Acetate