ASSOCIATION OF 4 ANTIGENS OF THE TETRASPANS FAMILY (CD37, CD53, TAPA-1, AND R2 C33) WITH MHC CLASS-II GLYCOPROTEINS/

Four of the tetraspans family antigens expressed in B cells, CD37, CD5 3, TAPA-1, and R2/C33, as well as at least two other molecules, CD19 a nd CD21, coprecipitate with DR antigens from mild detergent lysates of human B-cell lines and tonsillar B cells. Coprecipitation and preclea ring experiments indicate the existence of large multicomponent comple xes containing jointly the seven components, although some ''incomplet e'' complexes lacking some of the components may also exist. The compl exes contain only a relatively small fraction of the total cellular po ol of relevant molecules. The existence of these ''tetraspans-DR compl exes'' may be related to the previously reported antiproliferative and signaling effects of antibodies against most of their components.