Surface antigens of mammalian cells as genetic markers. II.

A second surface antigen, B(L), lethal in the presence of specific antibody and complement has been identified on some human cells and shown to behave as a good genetic marker. It is autosomal, unlinked to the human A(L) antigen previously described, and unlinked to 15 other human genes. The A(L) antigen, which is linked to the lactic dehydrogenase A gene, is found on the HeLa, the cultured human fibroblast, and in small amounts on the human lymphocyte. B(L) occurs on HeLa cells, on cultured human fibroblasts, and on human lymphocytes, but not on human RBCs. Hybrid cells formed by fusion of human and Chinese hamster cells have been prepared containing each of the four possible combinations of these two markers. Highly selective antisera sensitive to each marker separately can be obtained. The use of single-cell plating to demonstrate the presence of the antigens and of hybrid cells containing desired combinations of the markers facilitates study in this system.