Experimental transmission of the delta virus to a hepatitis B chronic carrier chimpanzee with the development of persistent delta carriage.

A delta virus (DV) infection was experimentally transmitted to a hepatitis B chronic carrier chimpanzee. The infection was monitored by the examination of liver biopsy materials with the use of FITC-labeled human anti-delta IgG or by an indirect immunoperoxidase staining technique and by measurement of the serum alanine aminotransferase (ALT) activity. Three different antibody enzyme immunoassays (EIAs) were developed for assessment of the serologic response: 1) blocking assay, 2) IgM-specific capture assay, and 3) IgG-specific capture assay. An antigen-specific EIA was also developed for monitoring delta antigen in the serum. The results indicate that a superinfection with the DV produced a biphasic ALT response concomitant with the appearance of the delta antigen in biopsy materials. The persistence of these markers over the observation period (350 days) indicates the development of a persistent DV infection.