Hemopoietic cell line distribution and immunoprecipitation of cell surface proteins recognized by two newly prepared monoclonal antibodies elicited by a human non-T, non-B leukemia cell line

Two newly prepared monoclonal antibodies elicited by a human non-T, non-B acute lymphoblastic leukemia cell line REH recognized distinct antigenic specificities characterized by the pattern of their immunofluorescence reactivities with a panel of hemopoietic cell lines and by immunoprecipitation of 125I-lactoperoxidase radioiodinated cell surface proteins, as well as periodate/tritiated borohydride radiolabeled cell surface sialoglycoproteins. Monoclonal antibody anti-p30 (BraFB6; IgG2b) recognized an antigen similar in its distribution to MHC class II antigens and immunoprecipitated a p30 cell surface protein, radiolabeled by lactoperoxidase catalyzed radioiodination. Monoclonal antibody anti-gp95 (BraEA10; IgG3) reacted in immunofluorescence intensively with non-T, non-B, T-leukemia and myeloid leukemia cell lines, less intensively with lymphoblastoid and lymphoma cell lines of B-phenotype and no reactivity was observed with examined non-hemopoietic human tumor cell lines. This antibody immunoprecipitated a lactoperoxidase radioiodinated and periodate/NaB3H4 tritium-radiolabeled cell surface sialoglycoprotein of approximately 95k (gp95) with variability in its apparent molecular weight, related to the origin of cells utilized for radiolabeling and immunoprecipitation.