Antigenic Relationship of a Hepatitis B Surface Antigen-derived Polypeptide and Human Serum Albumin

Department of Virology and Epidemiology, Baylor College of Medicine, Houston, Texas 77030, U.S.A. Four major polypeptides with mol. wt. of 22000, 25000, 52000 and 68000 were isolated from solubilized preparations of hepatitis type B surface antigen (HBsAg). These four populations, referred to as P22, P25, P52 and P68, respectively, were used to immunize guinea-pigs. Guinea-pigs were also inoculated with HBsAg and with purified human serum albumin (HuSA). These antisera were utilized to establish that intact HBsAg particles are associated with HuSA antigenic reactivity. HuSA antigenic determinants were associated with purified preparations of P68. HuSA antigenic activity was not detected with purified preparations of P22, P25 and P52 or with the respective specific antisera to each of the above. However, purified P68 contained the antigenic determinants of both host protein and hepatitis B virus-specified protein origin. Received 16 October 1979; accepted 3 January 1980.