Relation between non-A, non-B and delta hepatitis: studies with monoclonal antibodies.

To further investigate the specificity of the monoclonal antibodies (48-1 and S-1) associated with NANB hepatitis, extensive IF studies were carried out on liver biopsy specimens from chimpanzees with experimental hepatitis A, B, NANB, or D, 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 NANB 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 NANBV appeared to be longer than that of chimpanzees infected with HDV. By thin section EM, the presence of the microtubular aggregates, identical to those previously described for chimpanzees with NANB hepatitis and shown by immuno EM to react with the antibodies, was noted in hepatocytes during the acute phase of hepatitis D. The antibodies did not react with liver biopsy specimens from chimpanzees acutely or chronically infected with HBV, or HAV, 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 NANB agents and the HDV may have a similar nature or may elicit a similar host response.