Using both vascular smooth muscle strips (VSMS) and cultured cells (VSMC) from aortas of pigs, the contractile action of Bordetella heat-labile toxin (HLT) purified from B. parapertussis was studied in an attempt to elucidate the mechanisms of its action. HLT induced contractions in VSMC in parallel with the increase of Ca²⁺-influx. The HLT-induced Ca²⁺-influx and contraction were not influenced by verapamil or diltiazem, though a certain extension of the lag period was seen. The contractile action of HLT on VSMS and VSMC was not influenced either by diltiazem or quinacrine; that on VSMC was not influenced by prednisolone, indomethacin, aspirin, CV-3988, FPL-55712, ruthenium red, or TEAC. On VSMS, prednisolone caused the extension of lag period following HLT exposure. The action of HLT on VSMS was inhibited by TMB-8, whereas that on VSMC was not though the extension of lag period was seen. The HLT-induced contraction in both VSMS and VSMC was completely inhibited by H-7. The contraction in VSMS, but not in VSMC, was inhibited by H-8. HLT did not induce specific activation of the protein kinases in VSMC. The addition of cGMP or cAMP brought about relaxation in the HLT-exposed VSMS contracting in maximum. HLT caused a significant increase in permeability of VSMC membrane to trypan blue, accompanied with contraction. Both HLT-induced contraction and increase in permeability were inhibited by dextran of M.W. 8, 000, but not of M.W. 5, 000. These results suggested that HLT acted on vascular smooth muscle cells by damaging the membrane permeability, but not by disturbing the known cascades or systems for physiological contractions, resulting in the increase in Ca²⁺-influx and then contractions.

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Mycobacterium avium complex strains often contain considerably more numbers of viable bacterial units per mg wet weight than other mycobacteria, especially other slowly growing ones. This finding suggests that the life span of M. avium complex strains is often longer than the life span of other mycobacteria. The other mycobacteria, especially slowly growing ones seem to die more rapidly after their multiplication.

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The affinity constants of anti-canicola and anti-hebdomadis monoclonal antibodies and the numbers of antigenic determinants per organism of each serovar of leptospira were determined, and their influence on the results of microscopic agglutination test (MAT) and ELISA were examined. In the combinations of a monoclonal antibody and some serovar which showed higher affinity constants at levels of 10⁷ to 10⁸/M order, both MAT and ELISA were positive except for one combination, while in the combinations which gave lower affinity constants at levels of 10⁶/M order, MAT was positive but ELISA was negative. The number of antigenic determinants seemed to have no significant influence on the results. The disagreement due to the difference in the threshold affinities of MAT and ELISA should be considered in the use of monoclonal antibodies in the taxonomy of leptospira.

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Thirty-four female rats (18 days old) were infected with Streptococcus mutans MT8148R (serotype c) or 6715 (g). Diets containing different proportions of sucrose were used to prepare the dams which harbored various levels of S. mutans in their oral cavity. Around 66 days of age, the female rats were bred and 34 dams subsequently bore 322 offspring. The dams were killed upon weaning (20 days of age) of their respective litters. There were positive correlations between the recovery of inoculated S. mutans and the caries incidence in the dams. Transmission of S. mutans from a dam to her offspring was studied in 10-, 15-, 20-, 27-, 34-, 41-, 48-, and 55-day-old rats by evaluating the recover of S. mutans from the offspring. Positive correlation between the magnitudes of recovered S. mutans MT8148R from dams and their offspring was found in all ages of young rats examined. Furthermore, caries incidence in young rats was found to be positively correlated with the recovery of both strains of S. mutans as well as with incidence of caries in their respective dams.

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The binding of ¹²⁵I-labeled human plasma fibronectin (FN) to two strains of live Staphylococcus aureus (S. aureus) (a coagulase-positive Cowan I and a coagulasenegative Newman D2C) and the opsonic effect of FN on phagocytosis of these bacteria by human polymorphonuclear leukocytes (PMN) have been studied. ¹²⁵I-FN bound to a similar extent in both staphylococcal strains. The ¹²⁵I-FN-binding was significantly inhibited by human fibrinogen as well as unlabeled FN. The FN-binding was also reduced markedly by trypsinization of these bacteria, but the extent of its decrease did not correlate with their tryptic susceptibility of protein A and clumping factor. FN enhanced the uptake of these bacteria by PMN. However, its binding had no effect on superoxide anion (O₂^-) generation. The FN-binding definitely stimulated staphylococcal ingestion and intracellular killing by PMN, but the extent of such promotion was dissimilar between these two strains of bacteria. These results suggest that post-phagocytic metabolic activities as well as intracellular killing of these Staphylococci may also be greatly influenced by FN-unrelated factors as are other bacteria having no FN-receptors.

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A highly sensitive sandwich enzyme-linked immunosorbent assay to detect bacterial toxins was developed. Fab' of anti-toxin IgG was conjugated with horseradish peroxidase by the maleimide method and tetramethylbenzidine was used as substrate. As the solid phase, a 6.5mm diameter polystyrene bead was used and this was coated with the anti-toxin IgG. The entire assay could be completed within 3.5hr. The sensitivity of this bead-ELISA was found to be quite high with various bacterial toxins: less than 20pg/ml for thermostable direct hemolysin of Vibrio parahaemolyticus, less than 60pg/ml for Shiga toxin, less than 20pg/ml for VT2 (Shiga-like toxin II) of Escherichia coli, less than 200pg/ml for heat-labile enterotoxin of E. coli, and less than 6pg/ml for cholera enterotoxin.

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Strain Ictero No. I, the first isolate of Leptospira, isolated by Inada and Ido in 1914, was found to be sufficiently qualified to be the type strain of Leptospira interrogans rather than strain RGA. In an agglutinin absorption test, anti-Ictero No. I serum was not absorbed completely with strain RGA, and 25% of the homologous titer remained unabsorbed, while anti-RGA serum was completely absorbed with strain Ictero No. I. Thus, strain Ictero No. I was not serologically identical with strain RGA, and the two strains were considered to be different serovars. A protein band with a molecular weight of approximately 33, 000 daltons was detected in strain Ictero No. I but not in strain RGA by SDS-PAGE. By Western blotting, this protein band was detectable with anti-Ictero No. I serum but not with anti-RGA serum. The presence of the 33K protein in strain Ictero No. I, but not in strain RGA, was confirmed by radioimmunoprecipitation using [¹²⁵I]-labeled antigens, indicating that the protein antigen was surface-exposed. Only 8 of the 89 enzymes activities were different between strains Ictero No. I and RGA (line Sapporo). From the above results, we propose that strain Ictero No. I should be designated as the type strain of L. interrogans instead of strain RGA.

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A total of 53 Ad3 isolates obtained from patients with acute conjunctivitis in Japan, Australia, and the Philippines during 1973 to 1986 were analyzed for their genome types with 4 restriction endonucleases, BamHI, BglII, HindIII, and SmaI. Two new genome types designated tentatively as Ad3f and Ad3g were identified by combination of BamHI and BglII in the isolates. The changes of restriction sites and sizes of restriction fragments in newly recognized Ad3f and Ad3g were located at the similar regions reported in other Ad3 genome types by O'Donnell et al (1986) on physical maps of the Ad3 prototype strain GB genome. In Japan, 46 Ad3 isolates obtained from 1983 to 1986 were either Ad3f or Ad3g. Yearly alternation of predominance of both genome types were observed in the northern part of Japan during the period. In Australia, two genome types Ad3p and Ad3f were found in 6 isolates, and the former was observed in the 3 isolates obtained before 1981 and the remaining 3 isolates were obtained after 1983. In the Philippines, the only isolate obtained in 1984 was Ad3p.

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We investigated sex- and age-specific prevalences of hepatitis B e antigen (HBeAg) and antibody to HBeAg (anti-HBe) in 1, 163 carriers of hepatitis B surface antigen (HBsAg) in Okinawa, Japan, and followed them up for longer than one year in correlation with liver function abnormalities. Elevated serum transaminase levels were found in 160 (13.8%) of them. The prevalence of liver function abnormalities was significantly higher in male carriers (127/690, 18.4%) than in female carriers (33/473, 7.0%) at a P value of 0.001. In asymptomatic carriers, the prevalence of HBeAg was 13.2% and that of anti-HBe 80.0%, significantly different from 41.9% and 54.4%, respectively, in carriers with elevated transaminase levels (P< 0.001). In asymptomatic carriers, the mean age of HBeAg-positive carriers was 16.7 years which was much lower than the 22.8 years in carriers with liver function abnormalities. The prevalence of elevated transaminase levels was significantly higher in carriers with HBeAg than in those with anti-HBe (33.8% vs. 9.7%, P< 0.001). Based on these results, the prolonged positivity for serum HBeAg would qualify as a predictor for deteriorating liver function among HBsAg carriers.

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To determine when the hemophiliacs in Fukuoka prefecture, Japan, first became positive for antibodies, we tested human immunodeficiency virus (HIV) antibodies on serum samples obtained from 1976-1987 stored at -30C. Fifteen out of 64 hemophilia A patients (23.4%), five out of 11 hemophilia B patients (45.5%), but none of 17 patients with von Willebrand's disease (0%) were positive for HIV antibodies. In this series, two with hemophilia A became positive for HIV antibodies for the first time in 1983, and in 1984 another four with hemophilia A and one with hemophilia B became positive.

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The present study demonstrated that various reagents can specifically reduce the affinity of high-affinity interleukin 2 receptor (IL-2R) but not that of low-affinity IL-2R. They included lectins such as wheat germ agglutinin (WGA), concanavalin A and phytohemagglutinin, and a chemical cross-linker, glutaraldehyde, in addition to anti-IL-2R monoclonal antibodies, HIEI and H-47. The affinity of the high-affinity IL-2R was reduced when the cells were treated with WGA or H-47 before, but not after, addition of ¹²⁵I-labeled interleukin 2 (IL-2). Their inhibitory effects were also demonstrated by the chemical cross-linking method. On treatment with the reagents, the IL-2 binding to both IL-2Rα and β chains was inhibited and these inhibitory effects were seen only when the reagents were added before IL-2 addition, like their high-affinity reducing effects. These results support a supposition that the high affinity IL-2R is generated by assembly of the α and β chains, and suggest that the IL-2 binding to IL-2Rα and β chains could induce stable constitution of the high-affinity state of IL-2R, but these affinity modulating reagents could perturb the optimum association between α and β chains to generate the high-affinity IL-2R.

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In the course of study to obtain murine dendritic cell lines using oncogenic retroviruses, we have established several immortalized cell lines with characteristics different from those of dendritic cells. The transformants were mainly round nonadherent cells, capable of growing in soft agar, and negative for nonspecific esterase activity. Profiles of cell surface antigens were examined by indirect immunofluorescence technique. The cell lines were positive for Fc receptor (2.4G2), J11d (J11d.2), and B220 (RA3-3A1/6.1) antigens and negative (or dull positive in small percentages) for Ia (M5/144.15.2), IL-2 receptor (3C7), Thy-1 (B5-5), Mac-1 (M1/70.-15.11.5), and macrophage (F4/80) antigens. They were negative for both surface and cytoplasmic immunoglobulins. Several clones were established from these transformant cell lines and cell surface antigens were examined. Antigenic profiles of these clones were very similar to those of the parental cell lines. Some of these clones, however, seemed to increase their Ia antigen expression. The results suggest that the transformants originated from early B-lineage cells.

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