ABSTRACT6 agent of human origin was inoculated into four woodchucks chronically infected with woodchuck hepatitis virus (WHV). The animals developed 6 infections with serologic patterns similar to those previously observed in human and chimpanzee infections. 6 antigen was detected transiently in serum and liver and was followed by seroconversion to anti-6 antibody. Analogous to the chimpanzee model of 6 infection, serum and hepatocyte markers of WHV were suppressed in the woodchuck during acute 6 infection. The suppression of WHV DNA in serum was evident only during the time of 6-antigen positivity, while the inhibition of other WHV markers was more protracted. The 6 antigen in woodchuck sera circulated as an internal component of a particle similar in size to the human 6 particle (36-nm diameter) and was encapsidated by the woodchuck hepatitis virus surface antigen; 6 antigen from infected woodchuck and chimpanzee livers had similar biophysical properties. Histologic analysis showed that experimental 6 infection is associated with a transient acute hepatitis in woodchucks and loss of hepatocytes carrying WHV antigens. The lesions differed from the conspicuous hepatitis associated with reappearance of WHV replication. Hepatitis B-like viruses, therefore, appear to provide the requisite helper functions for 6 replication and the woodchuck represents a useful model for study of the virology and pathology of the 6 agent. (HCC) (8-10). Therefore, we investigated the possibility of using the WHV-infected woodchuck as a surrogate host for propagation of 8 agent of human origin.

Multiple cell types infiltrate acutely rejecting renal allografts. Typically, monocytes and T cells predominate. Although T cells are known to be required for acute rejection, the degree to which monocytes influence this process remains incompletely defined. Specifically, it has not been established to what degree monocytes impact the clinical phenotype of rejection or how their influence compares to that of T cells. We therefore investigated the relative impact of T cells and monocytes by correlating their presence as measured by immunohistochemical staining with the magnitude of the acute change in renal function at the time of biopsy in 78 consecutive patients with histological acute rejection. We found that functional impairment was strongly associated with the degree of overall cellular infiltration as scored using Banff criteria. However, when cell types were considered, monocyte infiltration was quantitatively associated with renal dysfunction while T-cell infiltration was not. Similarly, renal tubular stress, as indicated by HLA-DR expression, increased with monocyte but not T-cell infiltration. These data suggest that acute allograft dysfunction is most closely related to monocyte infiltration and that isolated T-cell infiltration has less acute functional impact. This relationship may be useful in assigning acute clinical relevance to biopsy findings.

Two populations of Dane particles were isolated from the plasma of individuals carrying hepatitis B surface antigen. These populations had densities in CsCl of 1.22 and 1.20 g/ml. Endogenous DNA polymerase activity was found to be associated only with the heavier of these two populations. Using a positive stain, electron microscopic examination of these particles suggested that the heavier the particle contained nucleic acid in its core whereas the lighter particle appeared empty. Cores isolated from Dane particles with densities of 1.22 and 1.20 g/ml banded in CsCl at densities of 1.36 and 1.30 g/ml, respectively. Endogenous DNA polymerase activity was associated only with the higher density core particles.

Balb/c mouse cells were persistently infected with RS virus. Continued passage of the virus produced in these Balb/c cells resulted in a 10-fold increase in the amount of infectious virus produced. Approximately 80% of the BCH4 cells expressed RNP and "spike" antigen intracellularly and associated with the cell surface. P. Cote et al., submitted for publication. 83