Further studies by immunofluorescence of the monoclonal antibodies associated with experimental non-A, non-B hepatitis in chimpanzees and their relation to D hepatitis.

To further investigate the specificity of the monoclonal antibodies (48-1 and S-1) associated with non-A, non-B hepatitis, extensive immunofluorescence studies were performed on liver biopsy specimens from chimpanzees with experimental hepatitis A, B, non-A, non-B or delta, or from normal chimpanzees. Both 48-1 and S-1 antibodies reacted in the same manner with liver biopsy specimens from 47 of 50 (94%) chimpanzees with acute or chronic non-A, non-B hepatitis and 15 of 18 (83%) chimpanzees with type D hepatitis. Examinations of serial liver biopsy specimens revealed that the duration of expression of the antigen reacting with the antibodies in hepatocytes of chimpanzees infected with non-A, non-B viruses appeared to be longer than that of chimpanzees infected with the hepatitis delta-virus. By thin-section electron microscopy, the presence of the microtubular aggregates, identical to those previously described for chimpanzees with non-A, non-B hepatitis and shown by immunoelectron microscopy to react with the antibodies, was noted in hepatocytes during the acute phase of hepatitis delta-virus. The antibodies did not react with liver biopsy specimens from chimpanzees acutely or chronically infected with hepatitis B virus or hepatitis A virus, or from normal chimpanzees. The present results confirm our previous observations with the 48-1 and S-1 antibodies. Furthermore, the finding that these two antibodies were also associated with hepatitis D would support the possibility that non-A, non-B agents and the hepatitis delta-virus may have a similar nature or may elicit a similar host response.