Isolation and Partial Characterization of Rat Lymphoid Cell Surface Histocompatibility Antigens and Immunoglobulins

Abstract

Cell surface molecules of rat normal lymphoid cells were selectively labeled by lactoperoxidase catalyzed iodination or by a galactose oxidase tritiated sodium borohydride technique, subsequently detergent solubilized, isolated by indirect immunoprecipitation and analyzed on SDS[sodium dodecyl sulfate]-polyacrylamide gel electrophoresis. Four polypeptide chains were isolated by using the alloantiserum DA anti-Lewis. The MW of the antigens were calculated as 41,000, 33,000, 27,000 and 12,000. Based on functional in vitro characteristics of the antiserum used and on the physiochemical properties and genetics of inheritance and tissue distribution, the polypeptide chains were identified as being subunits of Ag-B [major histocompatibility locus] and Ia [immune response associated] antigens. Two types of immunoglobulin [Ig] H-chains exhibiting the MW 70,000 and 64,000 were isolated from unfractionated normal spleen cells by use of a polyvalent rabbit anti-rat Ig serum and tentatively identified as .mu. and .delta. chain. Using the same anti-Ig serum, no molecules could be precipitated from the lysates of Lewis thymocytes or peripheral T [thymus-derived] cells.