Additional evidence for more than one agent of human non-A, non-B hepatitis. Transmission and passage studies in chimpanzees.

Abstract

Evidence supporting the existence of two agents of human non-A, non-B hepatitis was obtained by the inoculation of chimpanzees sequentially with serum from a chronically infected human (Inoculum I) and with fibrinogen prepared from pooled plasma (Inoculum IV), each of which had transmitted non-A, non-B hepatitis to humans. Passage inoculations of serum samples obtained during the acute stages of chimpanzee infections transmitted by either the agent in Inoculum I or IV also transmitted non-A, non-B hepatitis to additional chimpanzees. Transmission and passage of the agent in Inoculum IV were conducted in chimpanzees which previously had recovered from infection by the agent in Inoculum I. Cytoplasmic tubules in hepatocytes, which have been described during non-A, non-B hepatitis, were observed by electron microscopy in liver biopsies obtained during all infections transmitted by the agent in Inoculum I. These cytoplasmic tubules were not detected in liver biopsies from chimpanzees infected by Inoculum IV, except in one chimpanzee inoculated by Inoculum IV without prior exposure to the agent in Inoculum I. The cytoplasmic tubules observed in this study were found to be composed of transverse bands arranged with a periodicity of approximately 17 nm. These studies suggest that two different agents or distinct serotypes of human non-A, non-B hepatitis may have been present in these inocula, although reactivation of latent infection or reinfection could not be ruled out completely.