Experimental Infection of Chimpanzees with the Virus of Hepatitis B

Abstract

THE effects of viral hepatitis in chimpanzees are similar to those in man^1,2, and the disease can be transmitted from chimpanzees to humans³. Hepatitis B or Australia antigen (HBAg) has been reported in healthy chimpanzees⁴ and we have demonstrated antibody (HBAb) in 55% of these animals by radioimmunoassay. We have also shown the immunological identity between human and chimpanzee HBAg and HBAb⁵. Two susceptible chimpanzees (Xat and Yon) were inoculated intravenously with 1.0 ml. of a 1 : 10 dilution of human plasma containing HBAg and known to cause hepatitis B in humans. The animals were bled three times weekly and liver biopsies were obtained twice monthly in order to study immunological, biochemical, and histological responses. To determine HBAg, matrix gel diffusion (MGD)⁶, complement fixation (CF)⁷, radioimmunoassay (RIA)⁸ and passive haemagglutination (HA)⁹ techniques were used. To detect HBAg, the CF and MGD tests were used in addition to a “solid phase direct” radioimmunoassay system. Chimpanzee susceptibility to hepatitis B virus was inferred from a lack of demonstrable HBAb in serum by both HA and RIA techniques. Serum titre of HBAg in the diluted human plasma inoculum was 1 : 128 by the CF technique.