Spumaviruses isolated from sources containing agents of non-A, non-B (NANB) hepatitis do not cause NANB hepatitis.

Serum and liver tissue containing infective non-A, non-B hepatitis virus were shown to contain a retrovirus-like agent that replicated when inoculated into chimpanzee liver cell cultures in vitro. The virus appeared to assemble its core particles in association with tubular structures reminiscent of those characteristically seen in non-A, non-B hepatitis virus-infected chimpanzee liver in vivo, and produced syncytial cytopathic effects in a number of continuous and a primary mammalian liver cells. The agents were neutralized by acute and convalescent sera from human and chimpanzee cases of non-A, non-B hepatitis, as well as by antisera against simian spumavirus type 7, but not type 6. Aluminum chloride failed to abolish viral infectivity. There was no evidence of virus replication or hepatitis in chimpanzees inoculated with a seventh passage of one of the isolates. Thus the data suggest that the isolates are not causally related to non-A, non-B hepatitis, as was previously postulated.