Preparation of a drug-induced allergic hepatic disorder model with penicillin as hapten

A drug-induced allergic hepatic disorder model was established using a hapten and carrier. Penicillin G was bound to glycine for the preparation of N-hydroxy succinic imidylglycinyl benzylpenicillate (PG-Gly-OSu). Using this as the hapten and liver protein as the carrier, guinea pigs were sensitized with liver protein bound to PG-Gly-OSu. After 2 weeks, the sensitized guinea pigs were directly challenged with hepatocytes bound to PG-Gly-OSu through a mesenteric vein and hepatocellular disorder was induced. When the sensitized guinea pigs were challenged with PG-Gly-OSu alone or with liver protein alone, hepatocellular disorder could not be induced. These results suggest that the combination of PG-Gly-OSu as the hapten and liver protein as the carrier elicits a hepatocellular disorder similar to drug-induced allergic hepatitis.

Bacillus piliformis flagellar antigens for serodiagnosis of Tyzzer's disease

Purified flagella from multiple isolates of Bacillus piliformis were obtained and examined by electron microscopy. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot (immunoblot) analyses were used to assess the purity, antigenicity, and cross-reactivity of purified flagellar preparations. SDS-PAGE demonstrated a single, major protein band evident at approximately 53 to 56 kDa in all isolates tested. Results of Western blot analyses indicated a lack of cross-reactivity between flagellar antigens and heterologous isolates. Enzyme-linked immunosorbent assays (ELISAs) were used to compare the efficacies of flagellar preparations from the various isolates as antigens in detecting B. piliformis serum antibodies from several host species. ELISA results indicated that no single flagellar preparation could be relied on to consistently identify serum antibodies in all the host species tested; however, ELISAs that utilized a trivalent flagellar antigen preparation were shown to be specific and sensitive for the detection of antibodies to B. piliformis.

Role of hepatocytes and Kupffer cells in age-dependent murine hepatitis caused by a phlebovirus, Punta Toro

Punta Toro virus (PTV) infection of C57BL/6 mice results in fulminant hepatic necrosis and death in 3-week-old susceptible mice, but survival with minimal hepatocellular necrosis in 8-week-old resistant mice. Susceptibility in 3-week-old mice is associated with an earlier rise of viral titers in liver and serum than that occurring in 8-week-old resistant mice. There is also an earlier and more rapid accumulation of infectious progeny in serum vs. liver after PTV infection in both age groups, suggesting that the virus may replicate in extrahepatic sites as well as the liver. PTV infection of isolated hepatocytes and Kupffer cells from 3- and 8-week-old mice demonstrates a significant age-related difference in the ability of these cells to support replication of PTV in vitro (P less than 0.05). The age-related difference in liver cell-PTV interaction appears to be an inherent difference in the liver cells themselves, since there are no age-related differences in viral adsorption, morphogenesis, cytopathic effect, or interferon action within these cells. Thus, age-related differences in PTV replication or dissemination at extrahepatic sites, and the ability of the virus to replicate in intrahepatic sites, may be additive factors in the expression of age-related susceptibility to PTV in C57BL/6 mice.

Decreased toxicity of polymorphonuclear neutrophils toward hepatocytes isolated from rats with acute inflammatory reaction

We have recently demonstrated that polymorphonuclear neutrophils were toxic to hepatocytes through a protease-mediated mechanism. Since synthesis of antiproteases is markedly increased during acute inflammatory reaction, the aim of this work was to investigate the toxicity of neutrophils against normal vs. inflammatory rat hepatocytes. Acute inflammatory reaction was induced by subcutaneous injection of turpentine 24 hr before the experiments. Hepatocytes from normal and turpentine-treated rats were isolated by collagenase digestion. They were incubated with human neutrophils stimulated by 1 mg/ml opsonized zymosan. Cytotoxicity was quantified by the percentage of alanine aminotransferase activity released by hepatocytes in culture medium after an 18-hr incubation period. By comparison to normal hepatocytes, inflammatory hepatocytes were more resistant to the toxicity of neutrophils. At a neutrophil/hepatocyte ratio of 20:1, the alanine aminotransferase activity releases were 53.7% +/- 5.4% (mean +/- 1 S.E.) and 27.4% +/- 4.8% for normal and inflammatory hepatocytes, respectively. Similarly, inflammatory hepatocytes were found to be less sensitive than normal hepatocytes to the toxic effect of purified neutrophil cathepsin G. In contrast, both types of hepatocytes exhibited the same sensitivity to H2O2 generated by a system consisting of glucose and glucose oxidase. Two arguments suggested that the resistance of inflammatory hepatocytes to protease toxicity was explained by an increased production of antiproteases by these cells: (a) when tested against cathepsin G and porcine pancreatic elastase activities, the protease inhibitory capacity of conditioned medium from inflammatory hepatocytes was higher than that of conditioned medium from normal hepatocytes; (b) conditioned medium from inflammatory hepatocytes markedly reduced the toxicity of stimulated neutrophils as that of cathepsin G.(ABSTRACT TRUNCATED AT 250 WORDS)

Flow cytometric and functional analysis of mononuclear cells infiltrating the liver in experimental autoimmune hepatitis

Experimental autoimmune hepatitis was produced by immunizing Wistar rats with syngeneic liver proteins. Mononuclear cells infiltrating the liver tissue were identified by immunohistochemical techniques using monoclonal antibodies specific for subpopulations of rat lymphocytes. The strong infiltration of CD8+ cytotoxic T lymphocytes (CTL) were found in the portal areas. Subpopulations of mononuclear cells infiltrating the liver, spleen cells and peripheral blood lymphocytes were identified by flow cytometry. Flow cytometric analysis revealed the presence of CD5- and CD8+ lymphocytes in the liver tissues. Mononuclear cells infiltrating the liver were isolated from Wistar rats having autoimmune hepatitis to determine whether those exhibit cytotoxicity against syngeneic hepatocytes; they exhibited cytotoxicity against isolated syngeneic hepatocytes, but failed to lyse K562 cells, syngeneic concanavalin A-activated splenocytes and allogeneic hepatocytes. Depletion of CD8+ T cells significantly reduced the cytotoxic ability of mononuclear cells infiltrating into the liver against syngeneic hepatocytes. These findings support the idea that liver cell injury in experimental autoimmune hepatitis may at least in part be mediated by CTL.

Involvement of tumor necrosis factor-alpha in the pathogenesis of activated macrophage-mediated hepatitis in mice

The possible involvement of tumor necrosis factor-alpha in the pathogenesis of an experimentally induced hepatitis was investigated. Balb/c mice were primed with Propionibacterium acnes to induce the infiltration of mononuclear cells into the liver. Immunohistochemical study showed that most of the accumulated mononuclear cells at 7 days were Mac-2 positive, suggesting that they were activated macrophages. An injection of lipopolysaccharide resulted in massive hepatic necrosis and high mortality in the mice within 24 hours. Plasma tumor necrosis factor-alpha activity initially rose sharply and then declined over 3 hours. The increase in plasma aminotransferase activity correlated well with the elevation of plasma tumor necrosis factor-alpha activity. Pretreatment with dexamethasone or 16,16-dimethyl-prostaglandin E2 attenuated not only the elevation of plasma tumor necrosis factor-alpha activity but also the increase in plasma aminotransferase activity and improved the survival rate. Passive immunization against tumor necrosis factor-alpha showed protective effects. These findings suggest that tumor necrosis factor-alpha released from activated macrophages may play a crucial role in the pathogenesis of this murine hepatitis.

Autoantibodies to isolated human hepatocyte plasma membranes in chronic active hepatitis. II. Specificity of antibodies

The fine specificity of autoantibodies to human hepatocyte plasma membranes in autoimmune chronic active hepatitis was determined by one-dimensional immunoblotting. Sera from 12 patients with "classical" autoimmune chronic active hepatitis contained autoantibodies recognizing many human hepatocyte plasma membrane polypeptides in the 15 to 220 kD range. Many of these autoantibodies titrated beyond 1:80,000 and some may be potentially "pathological." In particular, one band with an apparent molecular weight of 60 kD was a dominant and consistent finding in all patients with autoimmune chronic active hepatitis by immunoblotting. Serum absorption studies showed this band to be predominantly liver-specific. Control sera from patients with chronic persistent hepatitis, nonhepatic autoimmune disease and normal healthy subjects possessed low titer reactivity that most likely represented "natural" autoantibodies. Anti-human hepatocyte plasma membranes in autoimmune chronic active hepatitis consisted of all three immunoglobulin isotypes (G,M and A) and their presence was not caused by nonspecific reactions as a consequence of hypergammaglobulinemia. Autoantibodies were shown to be specific by virtue of their absorption and exhaustion on titration. Many were directed at species nonspecific determinants, however, some autoantibodies recognized human-specific polypeptides. The majority of anti-human hepatocyte plasma membranes appeared to be organ-specific as sera from patients with autoimmune chronic active hepatitis reacted only weakly with polypeptides of kidney plasma membranes. Of the activity detected, few bands corresponded with those obtained using polypeptides of human hepatocyte plasma membranes. Our results show that patients with autoimmune chronic active hepatitis possess an array of liver-specific autoantibodies to polypeptide subunits of human hepatocyte plasma membranes.(ABSTRACT TRUNCATED AT 250 WORDS)

Extramucosal spread and development of hepatitis in immunodeficient and normal mice infected with rhesus rotavirus

The pathogenic profiles of two heterologous animal rotaviruses, rhesus rotavirus strain MMU 18006 and bovine rotavirus strain WC3, were evaluated in mice with severe combined immunodeficiency (SCID mice) and normal BALB/c mice. Control animals were inoculated with homologous murine strain EDIM 5099 or a tissue culture-adapted murine rotavirus. Heterologous infection with rhesus rotavirus resulted in hepatitis in 84% of SCID and 21% of BALB/c mice, with mortality rates of 27 and 0%, respectively. Surviving SCID animals developed chronic liver disease, while symptoms in BALB/c mice resolved in 2 to 4 weeks after onset. Histopathologic examination revealed a diffuse hepatitis with focal areas of parenchymal necrosis. Rotavirus was detected in liver tissue from 100% of 29 SCID and 85% (11 of 13) BALB/c animals tested by cell culture infectivity, immunofluorescence, or electron microscopy. No extramucosal spread of virus or hepatitis was observed after infection with heterologous bovine strain WC3 or homologous murine rotaviruses. This finding of a novel rotavirus-induced disease manifestation suggests altered tissue tropism in a heterologous host for a group of viruses previously shown to replicate exclusively in the gut mucosa. The implications of our observations suggest that in human vaccine trials utilizing heterologous rotavirus strains, special attention should be paid to children with immunodeficiency disorders, and screening for hepatic function should be included in vaccine protocols.

The significance of infections with two types of viral hepatitis demonstrated by histologic features in chimpanzees

In view of the recognized importance of necroinflammatory episodes in chronic hepatitis B virus (HBV) infection, chimpanzees, either HBV surface antigen (HBsAg) carriers or noninfected (naive), were infected with other primary hepatotropic viruses to evaluate histologic alterations and changes in virologic and biochemical markers of infection. The advantages of studies on chimpanzees are the availability of serial biopsy specimens and the viral type-specific histologic lesions, not as well recognized in humans. Infection with hepatitis A and non-A, non-B (NANB) agents produced more severe lesions in chronic HBsAg carrier chimpanzees than in naive animals. During this superinfection, the specific expression of the second agent was predominant, indicating that the exacerbation is caused by the second agent, but that carriers are prone to more severe disease than the naive chimpanzees. Hepatitis delta virus (HDV) infections were always coexistant with HBV and superinfection of carriers produced histologic changes more severe than those seen in any other type of viral hepatitis. Such HDV infections revealed less evidence of lymphocytotoxicity but rather of cytotoxicity, and sometimes resembled in appearance the histopathology of NANB. Coinfection of HDV and HBV and superinfection of HBV-carriers with NANB resulted in hepatitis that was far less severe than superinfection of HDV in HBV carriers, greatly in keeping with human experiences. HBV replication was suppressed transiently in both NANB and HDV superinfection. This implies that in exacerbations during chronic HBV infections of humans, suppression of HBV replication markers indicates superinfection, for instance, by NANB for which markers are so far not widely available; by contrast, elevated markers of HBV replication suggest reactivation of the original HBV infection.

Spontaneous development of organ-specific autoimmune lesions in aged C57BL/6 mice

We have shown that spontaneously occurring, organ-specific autoimmune lesions develop in aged C57BL/6 mice of both sexes, especially in 24-month-old senescent mice. The inflammatory lesions were found in the multiple organs such as salivary gland, kidney, pancreas, lung, and liver, associated with ageing process. Organ-specific autoimmune lesions first appeared in 6-month-old C57BL/6 mice, and were aggravated with advancing age. In contrast, significant inflammatory changes did not develop in the thyroid, stomach, testis, ovary, and prostate in aged C57BL/6 mice. The incidence and severity of organ-specific autoimmune lesions in this strain of non-autoimmune mice increase with advance of age. The most severely affected lesion was sialadenitis developed in the submandibular salivary gland of aged mice, and a significant difference between male and female mice was noted only in the salivary gland. The infiltrating cells within the lesions of multiple organs consisted mainly of Thy 1.2+ and L3T4+ cells. Autoantibodies were detected in the sera of the mice with each corresponding organ-specific autoimmune lesions.

[Combined immunodeficiency in LEC (Long Evans Cinnamon) rats with spontaneous hepatitis]

We investigated LEC rats immunopathologically which spontaneously developed hepatitis to find out the genesis, in comparison with non-hepatitis LEA (Long Evans Agouti) rats. 1) Wet weights of the spleen and thymus of 6-week old LEC rats were significantly lighter than those of LEA rats of the same age. 2) Serum IgG (Immunoglobulin G) in LEC rats remained markedly low after the age of two months and IgG antibody formation to SRBC (Sheep Red Blood Cell) as detected by plaque assay was also significantly suppressed. On the other hand, IgM antibody formation to SRBC was significantly suppressed through serum IgM level in LEC rats was normal or rather increased. 3) Blastogenic responses of spleen cells to PHA and Con A were much more suppressed in LEC rats than in LEA rats. 4) Cytostatic activity of intraperitoneal macrophages against tumor cells was more evident in LEC rats than in LEA rats, but there was no difference in NK (natural killer) activity between the two rat strains. From these results, it is speculated that spontaneously hepatitis-developing LEC rats possess T and B cell deficiency (combined immunodeficiency) and that the increase of macrophage and NK cell activities are linked to the genesis of developing hepatitis.

[Pathogenesis of spontaneous hepatitis in an inbred strain of LEC (Long Evans cinnamon) rats]

We have reported an inbred strain LEC rats with high frequency of spontaneous hepatitis. In this paper, we study a possible involvement of hepatitis virus, hereditary background, and correlation between serum IgG level and onset of hepatitis in LEC rats. Neither electron microscopy nor indirect immunofluorescent test could detect hepatitis virus article or antigen. Furthermore, we could not succeed in inducing hepatitis of LEA and WKA/H rats by injecting the serum, plasma and liver homogenates of the affected IEC rats, nor in promoting/developing hepatitis of LEC and LEA rats under the immunosuppressed condition by administration of steroid hormone. When we made a mating between LEC and non-hepatitis rats to investigate the hereditary mode, F1s had no hepatitis, but F2s and backcrosses developed hepatitis. We observed, in particular, the lower the serum IgG level was, the higher the rate of developing hepatitis was. From these results, we speculate that the involvement of hepatitis virus is not likely, but that a genetic mutation might cause low level of IgG and be also correlated with development of hepatitis.

Expression in transgenic mice of class I histocompatibility antigens controlled by the metallothionein promoter

To study the effects of increased expression of major histocompatibility complex class I molecules on the development of self-tolerance, transgenic mice were produced that expressed the H-2Kb gene under the control of the metallothionein promoter. Administration of zinc enhanced transgene expression in liver, kidney and exocrine pancreas. No evidence suggestive of an autoimmune response was found in transgene-expressing tissues in mice otherwise allogeneic to H-2Kb. Despite this lack of responsiveness in vivo, T cells could be stimulated in vitro to lyse H-2Kb-bearing target cells. No infiltration was detected in transgenic mice after irradiation and reconstitution with bone marrow cells. When spleen cells were used for reconstitution, however, dense lymphocytic infiltration was seen, particularly in the portal tracts of the liver, and this was accompanied by piecemeal necrosis and apoptosis of periportal hepatocytes. This aggressive response progressively diminished with time, and by 12 weeks after reconstitution many of the portal tracts were free of infiltration while the others showed no accompanying necrosis. The picture at this stage was similar to that seen in chronic persistent hepatitis. These results suggest that, in addition to negative selection in the thymus, peripheral mechanisms not involving clonal deletion or permanent clonal anergy can prevent immune responses to self molecules.

Adoptive transfer of experimental autoimmune hepatitis in mice--cellular interaction between donor and recipient mice

This report extends our previous study on experimental autoimmune hepatitis in C57BL/6(B6) mice. Cellular immunity involved in the induction of liver injury in this model was studied by transfer of primed spleen cells from hepatitis donor mice to syngeneic normal recipient mice. The most prominent liver damage in recipient B6 mice was induced by transfer of nylon wool adherent spleen cells from hepatitis donor mice, and T cells in this fraction were the essential requirement for the liver damage in the recipient mice. Nylon wool adherent spleen cells from hepatitis donor mice after depletion of the suppressor T-cell function by low-dose (300 rad) irradiation induced more severe liver injury compared to the same cells without irradiation. When the recipient mice were depleted of lymphocytes by low or high dose (700 rad) whole body irradiation, transfer of primed spleen cells from hepatitis donor mice did not induce liver lesion in the lymphocyte-depleted mice. This low susceptibility of lymphocyte-depleted recipient mice to primed spleen cells of hepatitis mice was no longer demonstrated after reconstitution with normal spleen cells. In a cell-migration study using 51Cr-labelled spleen cells, it was shown that a considerable number of infiltrating cells in the liver of recipient mice were derived from recipient mice themselves. These results seem to indicate that cell-to-cell interaction between radiosensitive precursor cells of recipient mice and liver-antigen-primed T cells from hepatitis donor mice play an essential role in the induction of liver injury in the recipient mice.

Inhibitory effects of prostaglandin E1 on T-cell mediated cytotoxicity against isolated mouse liver cells

The effects of prostaglandin E1 on cell-mediated cytotoxicity against hepatocytes were investigated using an in vitro cytotoxic assay system. Isolated liver cells from normal C57BL/6 mice were used as the target cells, and effector cells were obtained from spleens of C57BL/6 mice in which experimental hepatitis had been induced by immunization with syngeneic liver antigens. In this assay system, spleen T cells adhering to nylon wool demonstrated a high cytotoxic activity against target liver cells. The cytotoxicity was markedly reduced by prostaglandin E1 at concentrations greater than 10(-7) M. Maximum suppressive activity was obtained when prostaglandin E1 was continuously present during the assay period. By contrast, indomethacin, a specific inhibitor of prostaglandin synthesis, enhanced the cytotoxic activity of effector cells. These data seem to indicate that exogenously added prostaglandin E1 has an inhibitory effect on cell-mediated cytotoxicity of effector spleen cells against target hepatocytes.

Studies on the pathogenesis of murine experimental autoimmune active hepatitis: sensitized T cell involvement in its induction

Experimental autoimmune hepatitis was induced in B10.A(5R) mice sensitized by repeated intramuscular injections of syngeneic liver antigens emulsified with complete Freund's adjuvant. A 300R X-irradiation followed by two more injections after the sixth intramuscular sensitization to the mice resulted in active hepatitis with severe piecemeal necrosis. An intravenous adoptive transfer of spleen cells from the sensitized mice into normal syngeneic mice caused hepatitis in recipients which was characterized by extensive focal hepatic cell necrosis in the lobules. The transfer of spleen cells treated with monoclonal anti-Thy-1.2 antibody plus complement failed to induce hepatitis, while the transfer of T cell-enriched spleen cells by the panning method using rabbit anti-mouse immunoglobulin-coated dishes caused a somewhat more severe hepatitis than that caused by the transfer of whole spleen cells of the sensitized mice.

Effect of neonatal thymectomy on experimental autoimmune hepatitis in mice

Using an autoimmune hepatitis model of A/J mice which was prepared with immunization by syngeneic crude liver proteins, various influences of neonatal thymectomy were studied by observations of histological liver changes, autoantibody to liver-specific membrane lipoprotein (LSP), delayed-type hypersensitivity (DTH) to LSP, and purified protein derivative (PPD), and suppressor activity to LSP. The liver changes in the thymectomized mice were more intense than those in the non-thymectomized controls. Production of the anti-LSP autoantibodies and positive DTH to syngeneic LSP could be recognized in both groups of the thymectomized mice and the non-thymectomized controls, but the levels of those were higher in the former. In the level of DTH to PPD the thymectomized mice were lower than the non-thymectomized controls. Adoptive transfer experiments showed that suppressor activity to LSP was reduced in the spleen cells of neonatally thymectomized mice. This experiment suggests that neonatal thymectomy is apt to abolish tolerance to LSP on account of depressed suppressor activity to autoantigen, and accordingly liver damage is increased.

Study of cellular immunity in experimental autoimmune hepatitis in mice: transfer of spleen cells sensitized with liver proteins

This study was based on our model of experimental autoimmune hepatitis produced by immunizing C57BL/6 (B6) mice with syngeneic liver proteins and Freund's complete adjuvant. Spleen cells obtained from these hepatitis mice were transferred to syngeneic normal recipient mice, and histological changes occurring in the liver and the role of cellular immunity in producing liver damages in recipient mice were investigated. Sensitized spleen cells from these immunized (donor) mice were fractionated by a nylon wool column and injected intravenously into normal B6 mice. Histology of the liver of the recipient mice showed mild infiltration of mononuclear cells around the periportal area 7 days after the transfer of sensitized spleen cells, and changes were most prominent in the mice injected with the fraction of nylon wool column adherent spleen cells. Induction of these liver lesions in the recipient mice was blocked by treatment of sensitized donor spleen cells with anti-Thy 1,2 monoclonal antibody and guinea pig complement before injection. Lymphocyte reactivity to liver-specific lipoprotein (LSP) in recipient mice was studied by a lymphocyte transformation system, and a high immune response was demonstrated with the fraction of nylon wool column non-adherent (T-enriched) spleen cells. These data seem to indicate T-cell interactions between donor and recipient mice in the transfer study using our experimental autoimmune hepatitis model.

Genetically determined resistance to mouse hepatitis virus 3 is expressed in hematopoietic donor cells in radiation chimeras

Differences in mouse hepatitis virus 3 (MHV3) sensitivity among mouse strains are mainly determined by H-2-related and -nonrelated genetic factors. Reciprocal chimerism was therefore established between two H-2a compatible pairs of strains that differ widely in their susceptibility to MHV3: a) A/J and B10.A, respectively resistant and highly susceptible; b) A/J and A/Sn, respectively resistant and semisusceptible. Chimeric mice were challenged with 100 LD50 of MHV3, 30 or 90 days after X-irradiation (900 R) and bone marrow reconstitution. Results showed that sensitivity of recipients was similar either to that of the recipient strain or to that of the donor strain when chimeric mice were tested 30 or 90 days, respectively, after reconstitution. In addition, no paralysis occurred in surviving animals. These data indicate, therefore, that resistance or susceptibility to MHV3 is expressed intrinsically in some population(s) of hematopoietic-derived cells, which is radioresistant and has a life span of more than 30 days and less than 90 days. Additional experiments showed that X-irradiated A/J recipients reconstituted with A/J bone-marrow cells were protected against MHV3 challenge with spleen cells, with a mixture of spleen cell populations or of adherent spleen cells and thymocytes originating from A/J donors. Transfer of protection to recipients by using similar cell populations provided by semisusceptible A/Sn donors required the administration of five times more cells. Results suggest that two complementary mechanisms are required to confer resistance to MHV3: a) a gene(s) for resistance that may operate at the level of macrophages, and b) cells capable of mounting an efficient immune response. The reduced efficiency of A/Sn spleen cells suggests that semisusceptibility to MHV3 may be related to partial quantitative or functional immune defect.

Study of cellular immunity in experimental autoimmune hepatitis in mice

This study was undertaken to produce experimental autoimmune hepatitis in mice, and to examine the role of liver specific lipoprotein (LSP), if any, and of cellular immunity in such a model. After immunization of three strains of mice (C57BL/6, C3H/He and BALB/c) with syngeneic crude liver proteins, most prominent liver changes histologically mimicking human hepatitis were produced in the liver of C57BL/6 (B6) mice. Antigenic and immunogenic activity of LSP in the crude liver proteins was decreased by the treatment of freezing and thawing, and the recovery of the antigenic activity seemed to correlate with the susceptibility of immunized mice to the induction of liver damage. Autoantibody against LSP was demonstrated in the serum of immunized B6 mice, but not in the sera of other strains after immunization. It was also found that EDTA contained in the buffer used for purification of LSP distinctly suppressed lymphocyte activity in vivo and in vitro. With the use of EDTA free LSP, it was shown that spleen cells of immunized B6 mice (especially of T cell enriched fraction) had a high reactivity studied by lymphocyte transformation test. Further examination showed that EDTA free LSP could induce mild liver lesions and lymphocyte reactivity against LSP, although neither histological change nor lymphocyte reactivity was found in the liver of B6 mice immunized with EDTA containing LSP.

Purification by sucrose density gradient zonal centrifugation and affinity column chromatography of antigenic substances from the livers of mice infected with Tyzzer's disease

Antigenic substances from livers of mice infected with Tyzzer's disease were purified by means of sucrose density gradient zonal centrifugation and affinity column chromatography using antiserum and checking antigenicity with the complement fixation test. Fractions obtained from zonal centrifugation fell into three main groups with different molecular weights, two of which (Fr. I and Fr. II) positively reacted with antiserum in the complement fixation tests. Both fractions were further purified by affinity column chromatography. The molecular weights of the main antigenic substances derived from Fr. I and Fr. II were determined to be about 52 000 and 66 000, respectively, by means of SDS-PAGE.

Effect of experimental duck virus hepatitis infection on some biochemical constituents and enzymes in the serum of white Pekin ducklings

Experimental duck virus hepatitis infection of 11-day-old white Pekin ducklings having specific maternal antibodies revealed significant changes in some biochemical constituents and enzymes of the serum during the 3 weeks following exposure. These changes included a marked decrease in the total proteins and the albumin fraction, together with a significant elevation in levels of alkaline phosphatase, glutamic pyruvic transaminase, bilirubin, and creatinine. Most of these changes were attributed primarily to a deranged liver function associated with duck virus hepatitis infection.

Experimental autoimmune hepatitis in mice after immunization with syngeneic liver proteins together with the polysaccharide of Klebsiella pneumoniae

Experimental autoimmune hepatitis could be produced in SMA mice by monthly injections of syngeneic liver homogenate or liver-specific lipoprotein together with the polysaccharide of Klebsiella pneumoniae 03:K1 as a powerful adjuvant. Using a gel-diffusion technique, antibodies reacting with liver-specific lipoprotein and liver-specific membrane lipoprotein were detected in approximately 50% of sera from the immunized mice after an 8-mo period. After a full immunization schedule, 60%-80% of the livers of the sensitized mice developed infiltration of mono-nuclear cells consisting mainly of lymphocytes and plasma cells in portal areas, frequently associated with focal necrosis of hepatocytes. Moderate-to-severe piecemeal necrosis of hepatocytes appeared in 10 of 59 animals. However, a gradual decrease in the morphologic severity was observed 3-6 mo after cessation of injections. The transfer of splenic cells from animals with the damaged liver led to a hepatitis in recipients that was characterized by portal infiltration with mononuclear cells and by necrosis of liver parenchymal cells seen on day 14 after cell transfer. The suppressor cell activity determined by the ability of concanavalin A-activated cells to suppress blast transformation of splenic cells of normal SMA mice was significantly decreased (p less than 0.05) in mice immunized with a mixture of liver-specific lipoprotein and the polysaccaride of Klebsiella pneumoniae compared with mice immunized with the polysaccaride of Klebsiella pneumoniae alone or the polysaccaride of Klebsiella pneumoniae plus kidney lipoprotein.

Tuberculin hypersensitivity hepatitis in mice infected with Mycobacterium bovis (BCG)

A systemic BCG infection in mice induced multiple small granulomas located mainly in the periportal areas of the liver. Following systemic challenge of such mice with purified protein derivative of tuberculin (PPD), a rapidly developing hepatitis with diffuse intralobular mononuclear cell infiltration was precipitated, accompanied by high levels of aspartate transaminase in peripheral blood, hypoglycemia, focal hepatocyte necrosis, and accumulation of fibrinogen in liver. Bacterial lipopolysaccharide (LPS) also provoked acute hepatic damage both in BCG-infected mice and in mice pretreated with Corynebacterium parvum. PPD was not active in the latter. There were also lymphoid cell destruction and fibrinogen accumulation in the spleen of BCG-PPD-treated mice. Possible involvement of inflammatory and hepatotoxic mediators is suggested, and a T-lymphocyte-macrophage regulatory role in the pathogenesis of hepatitis is discussed.

Leukaemic liver infiltration in AKR mice prematurely induced by immunization with human or allogeneic liver protein

An attempt was made to produce a model of autoimmune hepatitis in AKR mice by immunization with allogeneic liver extract or a purified (human) liver-specific lipoprotein (LSP). Although a mononuclear infiltrate was found in the liver in recipients of purified liver antigen and to a lesser degree in recipients of allogeneic extract, this was associated with the development of an acute thymus-derived leukaemia. This mouse strain is normally susceptible to leukaemia after a latent period of approximately 6 to 9 months but the immunization schedule markedly reduced the age of onset of this disease.

Detection of liver IgG Fc receptors using soluble immune complexes of peroxidase-antiperoxidase. II. Detection in liver tissue from mice with D-galactosamine-induced hepatitis

The presence of liver IgG Fc receptor sites was demonstrated in the liver tissue from C-57 black mice with D-Galactosamine (GalN)-induced hepatitis by the localization of soluble immune complexes of peroxidase-antiperoxidase (PAP). Cryostat sections of liver tissues were incubated with the complexes and the peroxidase activity was revealed histochemically. In the normal liver tissue, PAP were localized on the Kupffer cells, some of the sinusoidal walls, and the liver cell membrane mainly at the side of the sinusoid. Twenty-four hours after single administration of GalN (1,500 mg/kg body weight), positive PAP reaction was mainly observed on the membrane surface of infiltrating cells in the area of hepatocellular focal necrosis, and faintly observed on the degenerative hepatic cell membrane and the sinusoidal walls. After 48 hours, these features became more remarkable, especially at the sites with severe necrotic lesions. After 72 hours, the positive reaction on the regenerative hepatic cell membranes again became distinct. At the chronic stage 13 weeks after repeated administrations of GalN and Freund's complete adjuvant, a strong positive reaction was found on swollen and multiplied Kupffer cells, and a faint one found on the liver cell membrane, especially at the periphery of the lobules; moreover, many PAP-positive infiltrated cells were found in the area of piecemeal necrosis. The relationship between liver IgG Fc receptors and the severity of liver cell necrosis is discussed.

Resistance to highly virulent mouse hepatitis virus acquired by mice after low-virulence infection: enhanced antiviral activity of macrophages

As early as 1 to 2 days after intranasal inoculation with a mouse hepatitis virus of low virulence, MHV-S, susceptible DDD mice became fully resistant to a normally lethal challenge with a highly virulent MHV-2. The resistance of MHV-S-pretreated mice was correlated with significantly decreased MHV-2 multiplication in the liver, spleen, and brain. Infection with MHV-S did not induce a high level of interferon in DDD mice, and no neutralizing antibody against MHV-2 was detected in the sera of mice until day 6 of MHV-S infection. The multiplication of MHV-2 was suppressed in peritoneal cells (PC) in vivo and peritoneal adherent cells (PAC) in vitro of MHV-S-pretreated mice was compared with those of normal mice. This suppression of virus multiplication was demonstrated in PAC collected during days 1 to 3 of infection but not in PAC collected from day 5 on. PC from MHV-S-pretreated mice were also suppressive to MHV-2 growth in DK cells as compared with PC from normal mice. By treatment of MHV-S-pretreated mice with silica, suppression of virus growth in the liver was partially diminished. These findings suggest that increased suppression of MHV-2 growth in PAC (mostly macrophages) of MHV-S-pretreated mice is responsible for resistance.

Immunologic phenomena in the effusive form of feline infectious peritonitis

The effusive form of feline infectious peritonitis (FIP) was reproduced by injecting 12- to 16-week-old kittens intraperitoneally with a cell-free inoculum derived from the tissues of infected cats. The kittens used for the study were either positive for FIP virus-reacting antibodies before inoculation or they were seronegative. Seropositive kittens were obtained from a cattery where the natural infection was enzootic, and seronegative kittens were obtained from a specific-pathogen-free cattery. Only about half the kittens that were seronegative before inoculation developed disease or serum antibodies to the tissue-derived virus. Seronegative kittens that developed disease showed no signs of illness until 8 to 10 days after inoculation, and they lived for 7 to 14 days after clinical signs appeared. The onset of clinical disease coincided with the appearance of serum antibodies. In contrast, all of the seropositive kittens became ill within 36 to 48 hours after inoculation, and died within 5 to 7 days. If seronegative kittens were treated with immune serum or immunoglobulin (Ig)G, they developed disease with the same frequency, acuteness, and severity as seropositive kittens. Foci of hepatitis and serositis in seropositive kittens contained viral antigen, IgG bound to antigen, and complement. Serum complement activity also decreased several days before death in seropositive kittens inoculated with tissue-derived FIP virus. The temporal relationship of clinical disease and the appearance of serum antibodies, the more acute and severe nature of the disease produced in seropositive kittens, and the presence of antibody and complement in the lesions indicated that effusive FIP is immunologically mediated.

Hepatitis B outbreak among chimpanzees at the London Zoo

Persistent carriage of hepatitis B virus in extremely high titre was identified in 5 out of 9 chimpanzees kept at the London Zoo. Antibody to this virus was present in the other 4 chimpanzees. Serological survey of the other primates in the Regent's Park collection did not reveal the presence of the surface antigen in 2 gorillas, 11 orang-utans, and 2 gibbons, although surface antibody was present in the serum of 1 gorilla and 2 orang-utans. 3 of the carrier chimpanzees were born at the Zoo and were the offspring of either a carrier mother or a carrier father, and perinatal transmission may have occurred. A strict safety code of practice was introduced and hepatitis B immunoglobulin was given at intervals to designated staff members. Sero-conversion did not occur in any of the 38 staff members under surveillance for more than 2 years. Treatment of the carrier state in the chimpanzees was attempted with human leucocyte interferon, with and without ribavirin ('Virazole'), and with adenine arabinoside, but the effects were mostly temporary.

Immunofluorescence of hepatitis A virus antigen in chimpanzees

Chimpanzee liver biopsies and necropsy tissues were examined by immunofluorescence for hepatitis A virus antigen. Results further indicate that the liver may be the sole site of replication for the virus.

Immunological abnormalities associated with liver disease: cause or effect?

Immunological abnormalities are demonstrable in patients with various types of liver damage. These may be (a) non-specific and unrelated to pathogenesis, e.g. auto-antibodies such as anti-nuclear factor; (b) specifically directed against liver antigens but not pathogenetic, e.g. cell mediated immune (CMI) reactions to liver antigen as seen in experimental carbon tetrachloride poisoning; (c) of such a nature as to modify the pathology produced by hepatotoxic agents, e.g. hepatitis B virus or alcohol; (d) primarily responsible for hepatic pathology, e.g. in idiopathic chronic active hepatitis. The latter two possibilities remain unproven although there is growing evidence that immune responses do play some role in the pathogenesis of acute and chronic hepatitis B and possibly also in the pathogenesis of alcoholic liver disease. It seems much less likely that primary abnormalities of the immune systems are responsible for any type of liver disease. In summary, therefore, the available evidence suggests that immune reactions could develop as a consequence of liver damage and only in certain circumstances do these reactions play a role in the development and continuation of hepatic pathology.

Genetics of macrophage-controlled resistance to hepatitis induced by herpes simplex virus type 2 in mice

The genetics of innate resistance of mice to hepatitis induced by herpes simplex virus type 2 (HSV-2) was analyzed by crossing resistant male GR to susceptible female BALB/c mice and backcrossing females of this F1 generation to susceptible male BALB/c mice. By scoring of macroscopic liver lesions and virus isolation studies from the liver 4 days after intraperitoneal inoculation of HSV-2, it appeared that the resistance was governed by one X-linked dominant gene or closely linked gene complex, as F1 female mice were resistant and F1 male mice were susceptible and the trait segregated in a ratio close to 1:1 in the backcross mating. A cellular expression in vitro of virus resistance was found in the macrophage population of the mice as measured by differences in the restriction of HSV-2 replication in macrophage cultures prepared from individual mice. In contrast to what was seen in macrophage cultures, virus replicated equally well in embryonic fibroblast cultures from susceptible and resistant strains of mice.

[Studies on hepatitis vaccines in geese (author's transl)]

Three passages of goose hepatitis virus of muscoy duck embryo cell cultures were used as a vaccine in geese. The offspring of birds inoculated with the thirty-second of fifty-fifth passage were found to be immune to experimental infection with virulent goose hepatitis virus. The fifty-fifth passage, inoculated intramuscularly, did not result in transmission of the virus, neither through the hatching egg nor by direct contact. The eight-seventh passage was non-pathogenic for susceptible day-old goslings and produced active and adequate immunity in these young birds.

Subtyping of hepatitis B surface antigen and antibody by radioimmunoassay

The hepatitis B surface antigen (HBSAg) has been shown to possess distinct subtypes adw, ayw, adr, and ayr). A commercially available solid phase radioimmunoassay for antibody to HBSAg (Ausab, Abbott Laboratories North Chicago, Ill.) has been modified to detect the subtypes of HBSAg as well as the subtype-specific anti-HBS reactivities to detect the subtypes of HBSAg as well as the subtype-specific anti-HBS reactivities (anti-d, anti-y, and anti-w). This method has the advantages of general availability, ease of performance, and increased sensitivity over conventional subtyping methods of agar gel diffusion and counterelectrophoresis.

Some properties of avian adenoviruses isolated from chickens with inclusion body hepatitis in Japan

Outbreaks of inclusion body hepatitis were observed in broiler chickens on a poultry farm during 3 years. Avian adenovirus-like agents were isolated during these years from livers of diseased chickens. Round-cell-type cytopathogenic effect and intranuclear inclusion bodies were produced in chicken kidney cell cultures inoculated with these agents. Properties of the agents were as follows: resistant to ether, chloroform, socium deoxycholate, trypsin, heating at 50 C, and pH 3.0; sensitive to 5-iodo-deoxyuridine; and pathogenic to chicken embryos. From these properties and ultrastructural findings of the agents, these were identified as avian adenovirus. Day-old commercial chicks were insusceptible to these viruses. Maternal antibody levels in commercial chicks were considerable. Surveys for neutralizing index to the virus were performed on chickens in the field, and all sera tested were positive. Electron-microscope examination showed that these viruses contained avian-adenovirus-associated virus.

Hepatitis A antigen isolated from liver and stool: immunologic comparison of antisera prepared in guinea pigs

Morphologically similar hepatitis A antigen particles (HA Ag)3 have been detected in the stools of patients with type A hepatitis and in the livers of marmosets experimentally infected with hepatitis A virus. To investigate the humoral antibody responses to these antigens and to compare the immunologic properties of HA Ag from these two sources, we immunized guinea pigs with either marmoset liver-derived HA Ag or with human stool-derived HA Ag in complete Freund's adjuvant and measured their antibody responses by immune electron microscopy (IEM) and immune adherence hemagglutination (IAHA). Antibodies reacting with both hepatitis A antigens were elicited in both groups. As determined by IEM, no distinction was seen between the reaction of guinea pig antiserum to each HA Ag tested under code when reacted against either liver-derived or stool-derived HA Ag. Antibodies elicited to marmoset liver-derived HA Ag and human stool-derived HA Ag had similar end point dilution titers by IAHA when tested against either "light" density (1.34 g/cm3) or "heavy" density (1.40 g/cm3) stool-derived HA Ag or liver-derived HA Ag. Low levels of antibody to normal liver or stool control antigens were observed transiently but did not obscure the specific response to HA Ag. These data suggest that morphologically similar HA Ag particles from different sources and with different densities are immunologically similar and may be identical. In contrast to the heterogeneity of surface antigens of hepatitis B virus, the comparable immunogenicity and apparent antigenic homogeneity of HA Ags derived from various sources may simplify the approach to development of a vaccine against viral hepatitis, type A.

Congenic strains of mice susceptible and resistant to mouse hepatitis virus

A congenic strain of C3HSS mice, which is histocompatible with C3H mice but differs from them in susceptibility to mouse hepatitis virus (MHV), has been developed by introducing the gene for susceptibility to the MHV-PRI virus from the PRI mice. This was accomplished by continual back-crossing of the hybrids to the C3H mice, but at the same time by selection of susceptibility by use of macrophage culture tests. After 20 back-crosses, a strain homozygous for susceptibility was produced by brother-sister mating of individual mice whose potential for carrying the recessive gene for resistance was tested in progeny. Since the original choice of mice for breeding was based on in vitro macrophage susceptibility, and since highly susceptible mice were developed on the same basis, it seems evident that macrophage susceptibility is an integral aspect of mouse susceptibility. The continued production of almost 50% susceptible mice in the back-crosses is further evidence of the dominant one-locus explanation of genetic susceptibility to this agent. Incomplete penetrance may also be present in 8 and 9 week old mice of the C3HSS strain since there was a sharp decrease in susceptibility of these mice even though their macrophages in culture maintained full susceptibility.

The role of circulating interferon in the modifications of immune responsiveness by mouse hepatitis virus (MHV-3)

MHV-3 modifies the humoral immune response to SRBC. During acute infections timing was critical: infecting mice before antigen administration led to immunodepression. Simultaneous injection with virus and SRBC resulted in immunostimulation. Persistent MHV-3 infections were associated with a chronic immunodepression. The presence of circulating interferon (IF) was well correlated with these modifications. IF peaking before antigen was associated with immunodepression whereas IF secretion after antigen was associated with immunostimulation. Low, permanent levels of IF were associated with chronic immunodepression. Since IF is, up to now, the only product of activated lymphocytes that has been shown to modulate immune responses, our results suggest that induction of IF by MHV-3 may be the main mechanism by which this virus modifies immune responsiveness. Moreover, we have shown that MHV-3 infection in susceptible mice diminishes the secretion of lymphocyte IF in response to Sendai virus. In these animals, the thymus cortex was profoundly depleted although the thymus medulla remained unchanged. The MHV-3 infection may, therefore, interfere with a subpopulation of IF-secreting lymphocytes. The possible physiologic role of such lymphocyte subpopulation in terms of host-virus relationships is discussed.

Role of the bursa of Fabricius in the pathogenicity of inclusion body hepatitis and infectious bursal disease viruses

Chickens were chemically bursectomized with cyclophosphamide at 3 days old, and studies made of the effects of infection by inclusion body hepatitis virus (IBHV) and infectious bursal disease virus. In another experiment, 3-week-old chickens were infected with infectious bursal disease virus before inoculation with IBHV. Interference with the bursa of Fabricius by cyclophosphamide or by infectious bursal disease virus enhanced the pathogenicity of IBHV. In contrast, cyclophosphamide effects on the bursa protected chickens against infectious bursal disease.

Carrier state of antibody and viruses in a mouse breeding colony persistently infected with Sendai and mouse hepatitis viruses

In a large-scale mouse breeder colony persistently infected with Sendai and mouse hepatitis viruses, most adult breeders 8 wk or more of age were shown to have antibodies to both viruses when monitored over a periof of 20 mo. Antibody to Sendai virus, apparently transmitted from the dam, was detected in 76% and 2% of mice aged 3 and 4 wk. respectively, and 64% and 100% of mice aged 6 and 8 wk, respectively. By seroconversion of sentinel cage-mates, a Sendai virus-carrier state was demonstrated with 6-wk-old mice but not with those either 4 wk or 10 wk of age, suggesting that breeder candidates about 6 wk of age may play an important role in establishing and perpetuating Sendai infection in this breeding colony. With mouse hepatitis virus, however, mice aged 4 wk or older seem to be effective transmitters of the virus, while some of these mice were found to have antibody to the virus.

Correlation of persistent mouse hepatitis virus (MHV-3) infection with its effect on mouse macrophage cultures

MHV 3 has three distinct effects in different strains of mice: strain A mice are completely resistant, most strains (including C57BL, DBA/2, BALB/c and NZB strains) die of acute hepatitis whereas in certain strains (eg. C3H and A2G) the virus produces a persistent infection with neurological symptoms. In cultures of peritoneal macrophages from susceptible strains, MHV-3 replicated freely, with giant cell formation. No replication was observed in macrophages from strain A mice. In contrast to this full susceptibility or resistance, macrophage cultures from strains of mice in which persistent infections occur showed an intermediate susceptibility, as judged by the intensity of the cytopathic effect, the presence of viral antigens in the cytoplasm and levels of viral replication. Possible ways in which the intermediate susceptibility of macrophages and persistent infections might be related are discussed.