PRODUCTION OF HUMAN MONOCLONAL-ANTIBODIES TO I-BLOOD-GROUP BY EBV-INDUCED TRANSFORMATION - POSSIBLE PRESENCE OF A NEW GLYCOLIPID IN CORD RED-CELL MEMBRANES AND HUMAN HEMATOPOIETIC-CELL LINES

To study the differentiation-associated glycolipid two anti-i mAb prod ucers, GL-1 and GL-2, were established from the combination of EBV-ind uced transformation of normal PBL and immune lysis of fluorescent dye- trapped liposome-containing bovine i-active glycolipid. The mAb GL-1 r eacted with both sialosylparagloboside and pentahexosyl ceramide and t he bovine i-active glycolipid whereas mAb GL-2 reacted only with the b ovine i-active glycolipid in LILA. Both mAbs cold-agglutinate human co rd red cells but not adult red cells. However, unexpectedly, the major ity of the reactivity of these mAbs in human cord red cells on TLC was not identical to the i-active glycolipid. The GL-1 antigenic substanc e is considered to be a glycolipid distinct from the i-active glycolip id because the immunoreactivity was canceled with endoglycoceramidase which cleaves a linkage between the oligosaccharide and ceramide. Base d on complement cytolysis with the mAb, 15 hematopoietic cell lines an d normal peripheral lymphocytes were screened for susceptibility to th e mAbs. A Burkitt lymphoma cell line, Ramos, was most sensitive among those tested, and BJA-B, Daudi, Namalwa in the B cell lines, TALL-1, J urkatt in the T-cell lines and HL-60 in the non-lymphoid cell lines we re sensitive whereas normal lymphocytes or other 8 cell lines were not . An immunoreactive spot with the same Rf with cord red cells was also detected in sensitive cell lines. The possible presence of a new glyc olipid antigen determined from the mAb and related to the differentiat ion of hematopoietic cells was speculated.