Alloantigens of human lymphoid cell lines; 'human Ia-like antigens'. Alloantigenic activity and cell line, organ and tissue distribution as determined by radioimmunoassay.

Membrane glycoproteins that appear to belong to a new alloantigen system were partially purified by gel filtration and lentil-lectin affinity chromatography from a non-ionic detergent (Renex 30) solubilized membrane fraction of each of two Burkitt lymphoma cell lines, B46M and Daudi. The preparations were radioiodinated and further purified by gel filtration, lentil—lectin affinity chromatography and anti-HLA antibody affinity chromatography. The labelled preparations thus obtained did not have binding activity with any of rabbit anti-HLA, rabbit anti-human β-microglobulin and rabbit anti-human IgG-Fab antisera, but did have a high level of binding activity with rabbit anti-B-cell membrane antiserum. Moreover, the labelled preparations showed relatively high binding activity with some conventional HLA typing sera. Out of sixty-eight human tissue typing alloantisera tested, three (Berlin 373, Betz and TO-29-01) gave especially high binding with both of the labeled preparations. The antigens involved in reaction with these alloantisera and also with the rabbit anti-B-cell membrane antiserum contained two components, one 31,000 ∼ 32,000 daltons and another 24,000 ∼ 25,000 daltons, bound non-covalently. The alloantigens were specific to B cell type cell lines (B-lymphoid cell lines and Burkitt-lymphoma cell lines) in cultured cell lines and also to B lymphocytes in peripheral blood. In organs and tissues, however, they were found to be present widely distributed in lymphoid organs (thymus as well as spleen and lymph node) and in non-lymphoid organs (including liver, kidney, testis and heart).