The effect of cellular immunity induced by tuberculous infection on bacteriological relapse after the termination of antituberculous chemotherapy was studied experimentally using immunodeficient nu/nu mice and immunocompetent dd mice. The efficacy of intensive chemotherapy was excellent even in nu/nu mice; tubercle bacilli in the organs decreased below the detectable limit, but formidable regrowth of bacilli was seen after the termination of chemotherapy. On the other hand, in the case of dd mice that established antituberculous cellular immunity through tuberculous infection, bacteriological relapse was generally very slight. It was concluded that bacteriological relapse was related closely with the established cellular immunity induced by the infected tubercle bacilli.

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We developed a novel method for the detection of Mycoplasma hominis from vaginal swabs using an indirect immunofluorescence technique. It is a rapid and simple method that can be finished in only 5hr and is more sensitive than the usual culture isolation method. The indirect immunofluorescence method was applied to vaginal smears from 193 healthy women and 33.7% gave a positive test. This value was much higher than that (11.4%) obtained from the same specimens by the culture method. When vaginal smears were subjected to Papanicolaou staining after the indirect immunofluorescence method, the specific immunofluorescence of the epithelial cells was located exactly at the sites of granular aggregates stained with Papanicolaou stain. A histological examination by Papanicolaou staining showed that the incidence of inflammation seems to be slightly higher in M. hominis-carriers than in non-carriers.

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In order to elucidate how virulence is controlled in encapsulated bacteria, some surface properties of an encapsulated but avirulent strain of Klebsiella pneumoniae, strain 277, were examined. Although strain 277 was heavily fimbriated, the fimbriae did not demonstrate an avirulent character and were not responsible for the surface hydrophobicity of this strain. The surface hydrophobicity was well correlated with the capacity of the bacteria to associate with polymorphonuclear cells. More bacteria with hydrophobic surfaces associated with the PMN than nonhydrophobic bacteria. The hydrophobic surface character of this strain was not affected by either trypsin treatment or extraction with salt solution. We assume that the capsule of strain 277 has more hydrophobic polysaccharides than that of the virulent strain. Some chemical modifications might therefore exist in the capsular polysaccharides of the avirulent strain.

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We examined mouse immune response to 4 kinds of recombinant vaccinia viruses carrying the HIV gag gene, including vac-gag/pol, which produces HIV-like particles with processed gag proteins; vac-gag, which also produces HIV-like particles but with unprocessed gag protein; and vac-gag-pol-fuse and vac-es-gag/pol, neither of which produces such particles but releases reverse transcriptase and gag protein, respectively, from infected cells. Although infection of mice with recombinant vaccinia viruses induced production of the anti-p24 antibody in all mice, vac-gag/pol and vac-es-pol induced higher production than the other two recombinants. Increase in [³H]thymidine uptake by splenic lymphocytes following p24 antigen stimulation was most evident in mice infected with vac-gag/pol. Thus, the highest immune reaction, both humoral and cellular, was elicited by vac-gag/pol, indicating that among those tested, this recombinant vaccinia virus is the best candidate for a vaccine that induces anti-HIV gag immunity.

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A complementary DNA (cDNA) that codes C-terminal, one-third of envelope glycoprotein (E) and N-terminal 65 amino acids of NS1 protein of Japanese encephalitis (JE) virus was inserted into Escherichia coli expression vector pRIT2T. The inserted gene was expressed as a fusion protein with protein A, and the expressed protein was intraperitoneally injected into mice. The immunized mice produced anti-JE antibodies measured by the hemagglutination-inhibition and neutralization tests as well as ELISA and were protected from the lethal challenge of JE virus by intraperitoneal inoculation.

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The fermentation-inhibition (FI) test for Mycoplasma pneumoniae was improved by using a combination of guinea pig complement and gamma globulin-depleted horse serum in place of unheated whole horse serum employed in the conventional assay system. As the test antigen for the new FI assay system, M. pneumoniae filtrated through a 3.0μm membrane filter was used. Owing to the strong augmenting effect of guinea pig complement, the FI activity of rabbit immune serum was increased 32-fold in the new system compared with the conventional system. Furthermore, IgM antibody, which is barely detectable by the conventional system, could easily be titrated by the new system. With this sensitive method, rapid rise of FI titer was clearly demonstrable in most children with acute M. pneumoniae infections, and a prevalence of FI or growth-inhibitory antibody among healthy adults in Japan (82%) was revealed.

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Effects of interleukin-4 (IL-4) on IL-6 production by human alveolar macrophages (AM) obtained by bronchoalveolar lavage from healthy donors was examined at the protein and gene levels. IL-6 production was quantitated by enzyme immunoassay (EIA) and bioassay using the IL-6 dependent murine hybridoma cell line MH60.BSF2. Results showed that when activated with LPS, AM released significantly more biologically active IL-6 than blood monocytes. Human rIL-4 significantly suppressed IL-6 production by AM and monocytes stimulated with LPS. Northern blot analysis revealed that IL-4 reduced the expression of IL-6 mRNA in LPS-stimulated AM and monocytes. The inhibitory effect was most pronounced when IL-4 was added with LPS or within the first 4hr after LPS to AM or monocytes. The suppressive effect of IL-4 was completely neutralized by pretreatment with anti-IL-4 antibody. IL-4 also showed a suppressive effect on IL-6 production by macrophages generated in vitro by maturation of blood monocytes with granulocyte-macrophage colony stimulating factor (GM-CSF). These observations suggest that IL-4 may play a critical role in in situ regulation of immune responses through suppression of IL-6 production.

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We have developed a monoclonal antibody, RTS-1, which can divide a rat CD8 (+) peripheral T cell population into two functionally distinct subsets. The cell-surface structure defined by this antibody is a glycoprotein with a molecular weight of 220kDa found to be a high molecular isoform of rat CD45 antigen. CD4 (+) T cells were not stained by RTS-1 antibody. The cytotoxic T cell-enriched population did not express RTS-1 epitope on the cell surface. CD8 (+) spleen cells as well as RTS-1(+)CD8(+)T cells exhibited strong inhibition on mitogen-induced immunoglobulin G production by rat B cells. Furthermore, RTS-1 antibody, but not the control antibody, abolished CD8(+)T cell-mediated inhibition of immunoglobulin G production by rat B cells. These data suggest that RTS-1 antibody recognizes a unique determinant of rat CD45 antigen that is expressed on a fraction of CD8(+) cells.

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Three strains of spirochetes (IKA1 to 3) were isolated from the midgut of Ixodes ovatus collected in the Ikawa region of the northern part of Shizuoka, Japan. These isolates had eight flagella, and their size and other morphological features were similar to Borrelia burgdorferi. They showed similar motility and reacted with monoclonal antibody (MAb) H9724 against borrelial flagella and with MAb H5332 against the outer surface protein A. These strains showed similar SDS-PAGE profiles to that of B. burgdorferi strain B31 and P/Bi isolated in the U.S.A. and Europe, respectively. Immunoblot with Lyme disease patient serum showed positive reactions with the flagella (41 Kilodalton, kDa), protein C (20 to 22kDa), and outer surface protein A (29kDa) of the isolates. Immunological properties, morphological characteristics, and epidemiological features revealed that these isolates were B. burgdorferi.

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The susceptibility to rifampicin and streptomycin of the Mycobacterium avium-Mycobacterium intracellulare complex was augmented by the addition of Tween 80 into 7H10 agar medium with OADC, whereas the susceptibility to ethambutol and sulfadimethoxine was either not changed or reduced by the addition of Tween 80. In 7H10 agar medium without OADC, however, susceptibilities to both rifampicin and sulfadimethoxine were reduced by the addition of Tween 80 to the medium. A number of hypotheses are made to explain these phenomena.

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