Failure of regulation of Tac antigen/TCGF receptor on adult T-cell leukemia cells by anti-Tac monoclonal antibody.
Anti-Tac monoclonal antibody, which blocks the membrane binding and action of human T-cell growth factor (TCGF), is strongly proposed to recognize TCGF receptor. We have demonstrated that anti-Tac antibody reacted with leukemic cells from patients with adult T-cell leukemia (ATL) and reacted with T-cell lines established from ATL cells. Although antigenic modulation, or down-regulation, of Tac antigen on activated normal T cells was induced by anti-Tac antibody, the expression of Tac antigen on ATL cells or T-cell lines was not affected when examined by the fluorescence-activated cell sorter (FACS) and the radioassay using 125I-staphylococcal protein A. These results indicate that regulation of Tac antigen-TCGF receptor is different between normal and malignant T cells, suggesting that failure of down-regulation of Tac antigen on leukemic cells by anti-Tac antibody may play an important role in the malignant proliferation of ATL cells.
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D002460:Cell Line; D006801:Humans; D007457:Iodine Radioisotopes; D007564:Japan; D007938:Leukemia / Q000503:physiopathology*; D007942:Leukemia, Experimental / Q000473:pathology; D011948:Receptors, Antigen, T-Cell / Q000502:physiology*; D011971:Receptors, Immunologic / Q000502:physiology*; D015375:Receptors, Interleukin-2; D013601:T-Lymphocytes
D000911:Antibodies, Monoclonal; D007457:Iodine Radioisotopes; D011948:Receptors, Antigen, T-Cell; D011971:Receptors, Immunologic; D015375:Receptors, Interleukin-2