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To investigate the efficiency of encapsidation of plasmid by papillomavirus virus-like particles (PV VLPs), and the infectivity of the resultant PV pseudovirions, Cos-1 cells were transfected with an 8-kb plasmid incorporating a green fluorescent protein (GFP) reporter gene (pGSV), and infected with bovine PV (BPV-1) L1/L2 recombinant vaccinia virus to produce BPV1 pseudovirions. Approximately 1 in 1.5×104 of dense (1.35 g/ml) PV pseudovirions and 0.3 in 104 of less-dense (1.29 g/ml) pseudovirions packaged an intact pGSV plasmid. The majority (>75%) of packaged plasmids contained deletions, and the deletions affected all tested genes. After exposure of Cos-1 cells to BPV-1 pseudovirions at an MOI of 40,000:1, 6% of cells expressed GFP, giving a calculated efficiency of delivery of the pGSV plasmid, by pseudovirions which had packaged an intact plasmid, of approximately 5%. Plasmid delivery was not effected by purified pGSV plasmid, was blocked by antiserum against BPV-1, and was not blocked by DNase treatment of pseudovirions, confirming that delivery was mediated by DNA within the pseudovirion. We conclude that a major limitation to the use of PV pseudovirions as a gene delivery system is that intact plasmid DNA is not efficiently selected for packaging by VLPs in cell-based pseudovirions production systems. [ABSTRACT FROM AUTHOR]

Cell mediated immunity (CMI) to hepatitis B viral antigens was studied in BALB/mice after immunization with purified hepatitis B surface antigen (HBsAg), or core antigen (HBcAg), with adjuvants. The two in vitro assays for cell-mediated immunity (CMI), utilizing lymph node cells, were release of interferon after exposure to antigen, and blast transformation of lymphocytes, and the in vivo assay was ear swelling at 24 h after local injection of antigen. Immunization with HBsAg or HBcAg with adjuvants induced antigen-specific cutaneous reactivity; if no adjuvants were given, immunization with HBcAg, but not HbsAg, induced cutaneous reactivity. CMI could be adoptively transferred by lymph node cells, but for only a limited period after immunization with HbsAg or MBcAg. The ability of lymph node cells from mice immunized with HBV antigens to transfer adoptively CMI correlated well with their production of interferon after challenge with antigen in vitro, but less well with blastogenesis after challenge with antigen in vitro, or with cutaneous reactivity to antigen in the donor mouse. Reliable antigen-specific lymphokine release assays, rather than blast transformation of lymphocytes or cutaneous reactivity after antigen challenge, arc required to assess CMI to HBV antigens in the mouse and, by inference, in man. [ABSTRACT FROM AUTHOR]

In 18 cases of chronic liver disease due to non-A, non-B hepatitis virus(es) in which the diagnosis was established by transmission, including chimpanzee inoculation in nine, sera were tested for the autoantibodies characteristically associated with autoimmune chronic active hepatitis. The frequency of autoantibodies to nuclear, smooth muscle, cytofilament, mitochondrial and liver membrane antigens was low, being not greater than that recorded for a normal population, and the few positive reactions obtained were at very low titre. These findings suggest that among cases of "HBsAg negative" chronic hepatitis, those due to NANB infection are distinguishable from those due to autoimmune chronic hepatitis by negative serological tests for autoantibodies. [ABSTRACT FROM AUTHOR]

An immunoradiometric assay for IgG class autoantibody to liver membrane antigens, based on serum binding to glutaraldehyde treated monkey hepatocytes, was used to examine sera from patients with chronic active hepatitis (CAH) and other acute and chronic liver diseases. All sera from normals and patients showed binding, up to a titre of 1/2,048. For comparison of assays, results were normalized by selecting two reference sera, one with a high degree of binding, and one from a healthy subject with a low degree of binding: at a dilution of 1/2,048, these sera were given binding values of 100% and 0%. The values for the binding of unknown sera at the same dilution were calculated from these two reference values. For 26 patients with autoimmune CAH, the mean (±s.d.) percentage binding value (70 ±33%) was significantly higher than the mean value for 26 healthy subjects (10±15%), and high binding values were significantly associated with biochemically active hepatitis. The mean percentage binding value was moderately increased for eight patients with HBsAg associated CAH (42±12%), 13 patients with alcoholic hepatitis with cirrhosis (37±25%) and 45 patients with acute viral hepatitis A (40±27%) or B (52±37%). At a cut-off binding value of 65%, the assay as a single diagnostic procedure was shown to have a 70% sensitivity and a 95% specificity for the diagnosis of autoimmune CAH. Better understanding of the pathogenetic significance of antibodies to liver membrane antigens in CAH and other liver diseases will depend upon biochemical analysis of the presumably multiple antigenic determinants on the hepatocyte membrane. [ABSTRACT FROM AUTHOR]

ABSTRACT- The mononuclear cell infiltrate in the liver was analyzed, using a panel of monoclonal antibodies (MAbs) of known specificity, in 10 patients with auto-immune chronic active hepatitis and, for contrast, in 14 with other types of chronic parenchymal liver diseases. In all cases, the mononuclear cell (MNC) infiltrate in the liver consisted mostly of T lymphocytes. Helper (Th) cells were more frequent than suppressor/cytotoxic T cells (Tsc) in the portal tracts and cirrhotic scar tissue, while Tsc were more common in the hepatic parenchyma. The number of Tsc cells in the parenchyma was greatest in patients with histologically active CAH and least in patients with quiescent cirrhosis. 'Plasmacytoid' cells with the morphology of plasma cells, a hallmark of the MNC infiltrate in auto-immune CAH, were more frequent in histologically active CAH than in quiescent cirrhosis. These plasmacytoid cells were T200 + ve, and hence of bone marrow origin, but the majority expressed neither membrane nor cytoplasmic immunoglobulin nor any lineage-specific marker antigens, and hence did not fulfil criteria for B lymphocytes; however, these cells were positive for OKT10 and HLA DR. No difference was evident between the MNC infiltrate in the liver in auto-immune CAH and that in the other acute or chronic liver diseases studied, including HBV-associated CAH; hence immunohistological studies do not point to any pathological processes uniquely responsible for the pattern of hepatocyte damage seen in auto-immune CAH. [ABSTRACT FROM AUTHOR]