No abstract

Murine Ia and human DR antigens were isolated and purified by immunoprecipitation and sodium dodecyl sulfate/polyacrylamide gel electrophoresis with allo-and xenoantisera, respectively. The I-A subregon antigen consists of two chains, designated Aa

No abstract

Platelets and human serum have been evaluated as sources for extraction of soluble HL-A antigens. 3 M KC1 was found to efficiently solubilize HL-A antigens from platelets with a recovery ranging between 50 and 100 %. However, because of the low density of HL-A determinants on platelets, the yield of sbluble antigens is low, as only 1 mg of protein can be recovered from 1 x l o 9 platelets. Thus, while it is difficult to solubilize sufficient antigens from platelets for chemical characterization, it is possible t o use these materials for biological applications such as pretreatment of kidney recipients. Soluble HL-A antigen is present in human serum, since following extensive ultracentrifugation, it can still effectively inhibit the cytotoxic activity of HL-A alloantisera. The same HL-A specificities were found to be present in varying amounts among different donors. Partial purification of such antigens can be achieved by ion-exchange chromatography of serum on QAE-Sephadex.