Encoding A New Human Activated B Lymphocyte Differentiation Antigen 5c5 Partial Cdna Cloning And Nucleotide Sequence Determination

Leukocyte differentiation antigens are a group of antigenic determinants on the membrane of human blood cells, that is one of the most important fields in the life sciences. Since 1982, five international conferences on this field have been held, and more than 130 CDs have been nominated. Among these CDs there are a few specifically expressed on B cell surface, and very few on the activated B cell surface.In 1991, we reported a differentiation antigen 5C5 expressed on human activated B lymphocyte surface. In order to confirm if antigen 5CS is a new differentiation antigen which has not been shown in literature, and in order to study its structure and function, antigen 5CS has been extracted and purified from 3D5 cell membrane lysates chromatographically on a colume conjugated with McAb 5C5 developed in our lab. Another McAb named 5C5-G1 has been made by immunization of BALb/c mice with antigen 5C5. The 3D5 cell is a humam activated B lymphocyte line established in our lab. McAb 5C5-G1 and McAb 5C5 recognize the same differentiation antigen. Western blot shows five protein bands of 92KD,52KD(± ), 40KD and 20KD respectively in reducing condition. Immunoprecipitation indicated two bands of 92KD and 52KD. Flowcytometric analysis shows that the antigen recognized by McAb 5C5-G1 and McAb 5C5 expresses on the same cells. They are human activated B cells and human activated B cell lines 3DS (stronge positive) and Daudi (weak positive). However resting B cells, resting T cells, activated T cells,...