The reactivity of sera from patients of Tsutsugamushi disease (scrub typhus) with the antigenic polypeptides of Rickettsia tsutsugamushi was analyzed by the immunoblotting method. The reactivity varied greatly among the sera of individual patients tested. IgG and IgM antibodies of most patients reacted with the 54-56 kilodalton (54-56K) polypeptide located on the rickettsial surface, suggesting that this polypeptide is a predominant antigen in the infection. Other polypeptides of 60K, 50-52K, 46-47K, 35K, and 21-25K were reactive with some but not all sera. From the reactivity of these polypeptides, it was suggested that the 54-56K polypeptide is both strain-specific and group-specific, the 60K polypeptide is group-specific, and the 35K and 21-25K polypeptides are subgroup-specific. IgG antibodies seem to be more cross-reactive with polypeptides of multiple strains than IgM antibodies and have a tendency of increased cross-reactivity that was observed in the sera obtained at the later stage of illness.

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The caries inhibitory activity of GOS-sugar (panose- and maltose-rich sugar mixture) was examined and compared with that of sucrose, maltose, or glucose in in vitro and in vivo experiments. Streptococcus mutans MT8148R (serotype c) and Streptococcus sobrinus 6715 (g) did ferment GOS-sugar and produce acid in a similar way as with maltose and glucose. However, GOS-sugar could not be a substrate for the glucosyltransferases (GTases) of these mutans streptococci to synthesize the water-insoluble glucan. Also, it significantly inhibited not only the synthesis of water-insoluble glucan from sucrose by the crude GTases but also the sucrose-dependent adherence of these cells to a glass surface. In particular, adherence of growing cells of 6715 was markedly inhibited by the presence of GOS-sugar. GOS-sugar was found to induce significant but minimal dental caries in SPF rats infected with either MT8148R or 6715. Furthermore, the replacement of half of the dietary sucrose content with GOS-sugar resulted in a significant reduction of caries development in rats infected with strain 6715.

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DNA restriction endonuclease analysis for genome typing of adenovirus (Ad) DNA was carried out on a total of 65 Ad isolates including serotypes Ad4, Ad7, Ad8, Ad11, Ad19, and Ad37 from patients with epidemic keratoconjunctivitis and acute conjunctivitis obtained in Japan from 1982 to 1986, Australia from 1973 to 1986, and the Philippines in 1984. All 4 isolates of Ad7 in Australia were Ad7b. Four of 6 Ad11 isolates obtained in Japan were typed as Ad11 prototype (Ad11p), and the remaining were identified to be new genome types, designated tentatively as Ad11c and Ad11d. An isolate of Ad11 obtained in Australia was typed as Ad11c. Nine Ad8 isolates in Australia and in the Philippines were typed as Ad8p, but 11 Ad8 isolates in Japan were Ad8b. Thirteen Ad19 isolates were identified as Ad19a. All 3 isolates of Ad37 in Japan and three isolates in Australia before 1982 were typed as Ad37p, however, 5 isolates in Australia after 1983 were identified as a new genome type, designated as Ad37d. In Japan, 10 isolates of Ad4 were identified as Ad4a.

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Recombinant human interferon alpha 2a as well as natural human interferons α and β significantly suppressed the production of hepatitis B surface antigen by PLC/PRF/5 cells (which have been established from a human primary hepatocellular carcinoma and proven to carry the hepatitis B virus DNA) and inhibited proliferation of these cells in vitro. However, the production of α-fetoprotein by PLC/PRF/5 cells was less significantly affected by any of the interferons. These results suggest that these interferons not only suppress cellular proliferation but also selectively inhibit the action of the HBV gene which is persistently present in these cells.

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Stimulation of macrophages with IgG2 immune complexes induced dose-dependently the O₂^- generation and the release of arachidonic acid and its metabolites. This Fc_γR-mediated O₂^- generation was inhibited by a phospholipase A₂ inhibitor, 4-p-bromophenacyl bromide (4-pBPB), in parallel to the dose-dependent inhibition of arachidonic acid release. The main arachidonic acid metabolites released were shown to be prostaglandin E₂ and thromboxane B₂ and blocking of the production of these metabolites by indomethacin did not inhibit the O₂^- generation. Inhibition of the Fc_γR-mediated O₂^- generation and the arachidonic acid release by the C-kinase inhibitor, 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7), was less intense than by 4-pBPB. These results support the previously proposed hypothesis that arachidonic acid acts as an intracellular activator of the Fc_γR-mediated O₂^- generation in macrophages. Although the C-kinase activation may also contribute to the activation of the O₂^--generating system, arachidonic acid release appears to play a major role in Fc_γR-mediated O₂^- generation. In contrast, activation of C-kinase seems to be contributing mainly in the induction of both the arachidonic acid release and O₂^- generation by 12-o-tetradecanoylphorbol 13-acetate (TPA). Furthermore, suboptimal concentrations of TPA and arachidonate were found to act synergistically to stimulate O₂^- generation and the inhibition study suggested a positive synergism between C-kinase and arachidonic acid release to induce O₂^- generation. This synergistic action may have general importance in receptor-mediated O₂^- generation.

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The effects of cholera toxin (CT) on delayed-type hypersensitivity (DTH) to sheep red blood cells (SRBC) were studied in mice sensitized by intranasal administration of SRBC. CT (1μg/mouse), given intranasally together with SRBC (2×10⁷/mouse), induced a maximally enhanced DTH response, which reached its peak around 7 days after sensitization, and also induced an accelerated DTH response upon a second administration of SRBC 28 days later. The ability of CT to enhance the DTH to SRBC was lost, either when CT was administered via the intraperitoneal or subcutaneous route, or when CT was introduced into the nasal site from which a large proportion of the SRBC was discharged 2 days after SRBC administration. These results indicate that the cells that are located in the nasal site and participate in the earlier events of DTH response were most affected by CT. The following effects of CT on the earlier events, which occur within 24hr after the intranasal administration of both CT and SRBC, appeared to be involved in the mechanisms by which CT enhances DTH to SRBC: (i) facilitation of the penetration of the antigen into the nasal tissue; (ii) reinforcement of the migration of immunocompetent cells from the blood to the nasal tissues; (iii) promotion of the ability of Ia-positive macrophages to present the antigenic determinants to T cells; (iv) facilitation of the differentiation of primed T cells to DTH-effector T cells.

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Japanese isolates of spotted fever group rickettsiae were observed under a transmission electron microscope. In Vero cells persistently infected with Japanese isolates, small numbers of intracytoplasmic rickettsiae were seen. On the other hand, moderate numbers of rickettsiae were found in the cytoplasm of productively infected BHK cells. The electron-lucent, halo-like zone was found to surround organisms in the cytoplasm of their host cells, which is a prominent characteristic of spotted fever group rickettsiae. Fine structural features of the cell wall revealed thin outer and thick inner leaflets like those observed in other spotted fever group rickettsiae.

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An enzyme-labeled complement fixation (ELISA-CF) test for the direct and quantitative determination of complement fixing (CF) antibodies has been developed. This paper described the introduction of the ELISA-CF test that used peroxidase-labeled Clq component of complement to detect CF antibodies which had reacted with herpes simplex virus (HSV), as a virus model. Equal volumes of heat-inactivated serum and the peroxidase-labeled Clq (P^*-Clq) were simultaneously added to wells of microplates which had been coated with HSV CF antigen or with cell control antigen. The enzymatic activities of P^*-Clq bound to the immune complex were determined photometrically. The ELISA-CF test allows processing of serum specimens in a 3-hr operation, with procedural simplicity and increased specificity and sensitivity compared with the conventional CF test.

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Bloodstream trypomastigote and cultured procyclic (insect midgut) forms of a monomophic strain of Trypanosoma gambiense were tested for their abilities to induce polyclonal B-cell activation (PBA) and immunosuppression (IS) in mice. Injection of a cell homogenate of bloodstream trypomastigotes induced both PBA and IS, while neither PBA nor IS was observed in mice injected with a cell homogenate of cultured procyclics. The results indicate that the substance(s) inducing PBA or IS is related to the developmental stage of the parasites.

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