A Cell Surface Antigenic Determinant Present on Mouse Plasmacytes and Only about Half of Mouse Thymocytes

Abstract

A new surface antigenic determinant present on a subpopulation of normal thymus cells of individual mice has been detected with rabbit antiserum obtained by immunization with cells of a mouse IgM-producing plasma cell tumor, MOPC-104E, and purified by in vivo absorption in mice. Cells of MOPC-104E and several other plasma cell tumors as well as a subpopulation of about 50% of normal mouse thymus cells were found to possess this antigen by cytotoxicity test. Although the present antigen is not plasmacyte-specific since it is also detected on thymocytes, it is not present on liver, kidney, or brain cells, as shown by absorption tests. Hence, it is clearly different from another mouse plasma cell antigen, which has been detected by rabbit antisera prepared similarly against the IgA-producing and IgG-producing plasma cell tumors, ADJ-PC-22A and MOPC-21, respectively, and which is common to liver, kidney, and brain.