Acetaminophen-induced immunosuppression associated with hepatotoxicity in mice

We investigated the influence of acetaminophen (APAP), an analgesic and hepatotoxic agent, on the immune system in mice. The activity of serum glutamic-pyruvic transaminase was markedly increased by about 200 fold compared to that of the vehicle control following intraperitoneal injection of 400 mg/kg of APAP. In vivo antibody-producing responses to SRBC was significantly inhibited by APAP in a dose-dependent manner, while in vivo T cell-independent antibody-producing responses to TNP-Ficoll was not inhibited. The addition of thymocytes from APAP-treated mice suppressed the response to SRBC in vitro. Thymocyte blastogenesis following mitogenic stimulation with concanavalin A was also inhibited by injection of APAP. The delayed-type hypersensitivity response and mixed lymphocyte reaction, which are used to evaluate cell-mediated immunity, were also significantly reduced after treatment with APAP. These results indicate that APAP suppresses the humoral and cell-mediated immune responses at a dose that causes liver injury.     

Use of glycopeptidolipid core antigen for serodiagnosis of mycobacterium avium complex pulmonary disease in immunocompetent patients

We report the development of a serodiagnostic method for Mycobacterium avium complex (MAC) disease with an enzyme immunoassay (EIA) with the MAC-specific glycopeptidolipid (GPL) core as the antigen. In this study, we confirmed by EIA that the GPL core antibody was in the sera of immunocompetent patients with MAC disease. The EIA for quantifying the GPL core antibody was evaluated as a clinical tool for serodiagnosis of pulmonary MAC disease. A significant increase in GPL core antibodies (immunoglobulins G, A, and M) was detected in sera of patients with MAC pulmonary diseases when they were compared to patients who were colonized with MAC, patients with Mycobacterium kansasii disease or tuberculosis, and healthy subjects. The sensitivities and specificities of the GPL core-based EIA for diagnosis of MAC pulmonary disease were 72.6% and 92.2%, respectively, for IgG, 92.5% and 95.1%, respectively, for IgA, and 78.3% and 91.0%, respectively, for IgM. The best sensitivity and specificity were obtained by measuring immunoglobulin A antibodies against GPL core antigen. The level of GPL core antibodies reflected disease activity, since it decreased in cured MAC patients who had responded to chemotherapy. Measurement of serum antibodies against GPL core is useful for both diagnosis and assessment of disease activity in MAC disease of the lung.     

Immune response to Trichomonas vaginalis. IV. Immunochemical and immunobiological analyses of T. vaginalis antigen

The immune response of patients with trichomoniasis vaginitis to Trichomonas vaginalis was examined by using passive hemagglutination assay and skin reactions. Trichomonas-specific immune responses could hardly be detected in the patients by these assay methods. In order to develop a simple and reliable assay for demonstration of T. vaginalis-specific immune responses in the patients, proliferation responses of peripheral mononuclear cells from the patients were examined. Lymphocytes obtained from the patients were shown to incorporate 3H-methyl-thymidine when stimulated with T. vaginalis antigen in vitro. Furthermore, immunochemical analysis of T. vaginalis antigen has been done by Sephadex chromatography and sodium dodecyl sulfate gel electrophoresis. The data revealed that the murine and human IgM antibodies specific to T. vaginalis recognize various antigens with a wide range of molecular weights (between 13,000 and 100,000 daltons), while human and murine IgG antibodies recognize molecules with a much narrower range of molecular weights (50,000-100,000 daltons).     

Trehalose 6,6'-dimycolate (cord factor) of Mycobacterium tuberculosis induces foreign-body- and hypersensitivity-type granulomas in mice

Granulomatous inflammation is characterized morphologically by a compact organized collection of macrophages and their derivatives. It is classified as either a hypersensitivity type or a foreign-body type. Lipid components of the Mycobacterium tuberculosis cell wall participate in the pathogenesis of infection. Strains of M. tuberculosis have cord factor (trehalose 6,6'-dimycolate [TDM]) on their surface. To clarify host responses to TDM, including immunogenicity and pathogenicity, we have analyzed the footpad reaction, histopathology, and cytokine profiles of experimental granulomatous lesions in immunized and unimmunized mice challenged with TDM. In the present study, we have demonstrated for the first time that TDM can induce both foreign-body-type (nonimmune) and hypersensitivity-type (immune) granulomas by acting as a nonspecific irritant and T-cell-dependent antigen. Immunized mice challenged with TDM developed more severe lesions than unimmunized mice. At the active lesion, we found monocyte chemotactic, proinflammatory, and immunoregulatory cytokines. The level was enhanced in immunized mice challenged with TDM. This result implies that both nonimmune and immune mechanisms participate in granulomatous inflammation induced by mycobacterial infection. Taken together with a previous report, this study shows that TDM is a pleiotropic molecule against the host and plays an important role in the pathogenesis of tuberculosis.     

Natural antibodies against the immunoglobulin F(ab′)2 fragment cause elimination of antigens recognized by the F(ab′)2 from the circulation

A humanized monoclonal IgG1 antibody, designated hC4G1, recognizes the fibrinogen receptor glycoprotein (GP)IIb/IIIa on platelets and inhibits platelet aggregation. When the F(ab′)₂ fragment of hC4G1 (F(ab′)₂ hC4G1) was administered to cynomolgus monkeys, all the monkeys showed inhibition of platelet aggregation ex vivo. Unexpectedly, a significant decrease in platelet count was observed in 5 of 18 monkeys. Antibodies against F(ab′)₂ hC4G1 were detected in the plasma of these monkeys by ELISA. Antibody activity in the plasma of these monkeys was significantly correlated with the intensity of platelet decrease (r = 0.84). The natural monkey antibodies to F(ab′)₂ hC4G1 were directed against the C-terminal region of F(ab′)₂ fragment common to all human and humanized IgG antibodies. Natural homo-reactive antibodies were also detected in human plasma from 15 of 40 healthy volunteers. Specificity was closely similar to that of the monkey antibodies. Affinity-purified human homo-reactive antibodies enhanced phagocytosis of platelets treated with the F(ab′)₂ hC4G1. Monkey plasma with high homo-reactive antibody activity was confirmed to decrease platelet count when administered together with F(ab′)₂ hC4G1 to a monkey with low antibody activity. These results suggest that F(ab′)₂ of humanized and human antibodies causes elimination of the corresponding antigens from the circulation by homo-reactive antibodies.     

Control of feeding rhythm in the terrestrial slug Incilaria bilineata.

A modulatory neuron of feeding rhythm was newly identified in the buccal ganglia of the isolated central nervous system (CNS) of the terrestrial slug Incilaria bilineata. This neuron was termed the "feeding rhythm modulator" (FRM). Its morphological and electrical properties were compared with those of the MGC (metacerebral giant cell, a cerebral modulatory neuron of feeding rhythm). There was no direct connection between FRM and MGC. In order to investigate the control mechanism of the buccal central pattern generator, feeding rhythm was observed by varying the activities of MGC and FRM simultaneously. At a lower level of activity of MGC, feeding rhythm was not only sensitive to the activity of MGC but also to that of FRM. As the level of activity of MGC increased, feeding rhythm was exclusively controlled by the activity of MGC, and became unaffected by the activity of FRM. This indicates that cerebral neurons such as MGC primarily control feeding rhythm and modulate the contribution of FRM in a hierarchical manner.     

Structure-activity relationship of mycoloyl glycolipids derived from Rhodococcus sp. 4306

Novel mycoloyl glycolipids with short carbon chains were isolated and purified from Rhodococcus sp. 4306, a soil origin of Actinomycetales. Their chemical structures were identified as trehalose 6,6'-dimycolate (TDM), trehalose 6-monomycolate, glucose 6-monomycolate, mannose 6-monomycolate and fructose 6-monomycolate. The length of carbon chains and number of double bonds of mycolic acids were C(34), C(36)and C(38)saturated, monoenoic and dienoic molecular species, which were much shorter than those of Mycobacterium tuberculosis (C(78-88)monoenoic and dienoic). Among them, only TDM could induce prominent granulomatous inflammation of the lung and spleen in mice. By contrast, other mycoloyl glycolipids induced mild lesions. The small-sized TDM of Rhodococcus possessed granulomatogenic activity, however, the toxicity was much lower than that of M. tuberculosis. Rhodococcal TDM was composed of mycolic acid with the shortest carbon chains, when compared to granulomatogenic TDM of Mycobacterium, Nocardia and Rhodococcus reported previously. Our results imply that rhodococcal TDM is a pathogenetic factor similar to that of M. tuberculosis, although rhodococcal TDM exhibits low toxicity.     

Control of feeding rhythm in the terrestrial slug Incilaria bilineata

A modulatory neuron of feeding rhythm was newly identified in the buccal ganglia of the isolated central nervous system (CNS) of the terrestrial slug Incilaria bilineata. This neuron was termed the “feeding rhythm modulator” (FRM). Its morphological and electrical properties were compared with those of the MGC (metacerebral giant cell, a cerebral modulatory neuron of feeding rhythm). There was no direct connection between FRM and MGC. In order to investigate the control mechanism of the buccal central pattern generator, feeding rhythm was observed by varying the activities of MGC and FRM simultaneously. At a lower level of activity of MGC, feeding rhythm was not only sensitive to the activity of MGC but also to that of FRM. As the level of activity of MGC increased, feeding rhythm was exclusively controlled by the activity of MGC, and became unaffected by the activity of FRM. This indicates that cerebral neurons such as MGC primarily control feeding rhythm and modulate the contribution of FRM in a hierarchical manner.     

Confluent BALB/c 3T3 cells monolayer provides selective and efficient growth of neoplastic cells

In an attempt to further characterize non-irradiated contact-inhibited confluent monolayer of BALB/c 3T3 cells (= Contact-Sensitive Plates; CSP) as substrata for in vitro drug sensitivity testing, we compared the efficiency of colony formation with panels of cell lines on CSP with that on plastic dishes or in agar. Tumorigenicity in athymic nude mice was also examined. We found that: (1) HeLa cells, 2 esophageal cancer lines, rat 3Y1 fibroblasts transformed by either adenovirus type 12, mouse polyoma virus, Rous avian sarcoma virus, or plasmid DNA carrying v-Ha-ras oncogene all formed colonies on CSP and in agar and at the same time was tumorigenic. The efficiency of colony formation on CSP proved always to be higher than that in agar. (2) None of the 4 "normal" fibroplastic cell lines formed colonies on CSP or in agar and were tumorigenic. (3) Simian virus 40 and adenovirus E1A gene transformed rat 3Y1 fibroblasts formed colonies on CSP but not in agar, and were not tumorigenic. Therefore, CSP was found to provide selective and efficient growth of neoplastic cells when compared to other substrata and is also helpful in detecting incompletely transformed cells.