The immunobiology of lipopolysaccharide (LPS) of Salmonella typhimurium LT2-71 was studied in its native, modified and conjugated states using mice as the experimental model. An alkali-treated detoxified fraction of LPS (D-LPS) was found to be not only non-toxic but also equally immunogenic, like LPS. In addition D-LPS alone or conjugated with enterotoxin or hemolysin was also non-pyrogenic and non-indurogenic. The immunoprophylactic activity of D-LPS conjugates to a 100 ID₅₀ challenge dose of S. typhimurium was also higher than that of detoxified LPS or native LPS.

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A marked serological cross-reactivity was observed by ELISA and a precipitation test between anti-Proteus mirabilis O23 serum and the lipopolysaccharide as well as the O-specific polysaccharide from the Proteus mirabilis strain belonging to serogroup O6. The structures of the O-specific polysaccharides were elucidated using chemical and NMR spectroscopic analyses, and the only common component, 2-acetamido-2-deoxy-β-D-glucopyranose (β-D-GlcNAc), was revealed, which was suggested to be responsible for the cross-reactivity observed. Both anti-O23 and anti-O6 sera were shown to react with 1, 3-linked β-D-GlcNAc-containing O-antigen from Salmonella enterica ssp. arizonae O59 also. The lack of reactivity of Smith-degraded P. mirabilis O6 O-specific polysaccharide with homologous antiserum indicated the crucial role of α-D-glucuronic acid in specific antibody binding.

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The shotgun cloning of a Mycobacterium bovis BCG (BCG) genome into pBluescript SK (+) successfully yielded a 0.9kbp fragment, confirming the ability of Escherichia coli thyA mutant MH2702 to grow in a thymine-depleted medium. This DNA fragment contained a gene homologous to the thymidylate synthase (TS)-encoding genes (thyA) of other organisms. An inverted repeat sequence and open reading frame (ORF) were observed at the upstream region of the thyA. A computer analysis revealed that the protein encoded by this ORF possessed a structure unique for a DNA binding protein.

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The monoclonal antibody 21E7-B12 (IgG₃) can be used in a direct method of Clostridium tyrobutyricum detection based on an immunoenzymatic assay. Immunoelectron microscopy demonstrated that the 21E7-B12 antibody recognized the surface-exposed epitopes on the flagellar filaments of C. tyrobutyricum. After flagellar extraction, the purified flagellin showed an apparent molecular mass of 46kDa with an isoelectric point of 3.6. Sugar staining, mild periodate oxidation and β-elimination experiments showed that the flagellin was glycosylated and that the 21E7-B12 epitope was located in the sugar moiety. Amino acid composition showed that the flagellar filament protein contained a high percentage of serine and threonine, while proline was absent. The first 23 residues of the N-terminal were determined and sequence homology with other flagellins was found.

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The extracellular slime produced by Staphylococcus epidermidis has been shown to interfere with several human neutrophil functions in vitro, such as chemotaxis, degranulation and phagocytosis. Slime production has been suggested as a useful marker for clinically significant infections with coagulase-negative Staphylococcus. Since the main role of macrophages in defense mechanisms is phagocytosis, the effect of slime on the phagocytic activity of macrophages was investigated. The phagocytic activity of murine peritoneal macrophages treated with slime in vitro decreased in a dose-dependent fashion. A similar decrease was also observed in macrophages isolated from mice that had previously received intraperitoneal injection of slime. To investigate whether interferon also plays a role in this process, mice were treated with interferon or an interferon inducer, polyinosinic-polycytidylic acid (poly I:C), together with slime before macrophage isolation. The slime-suppressed phagocytic activity of macrophages was partially relieved by both agents, and the recovery effect of poly I:C in slime-suppressed phagocytosis of macrophages in vivo might be attributed to the increased interferon level in peritoneal fluid and sera. However, when slime was given to poly I:C-pretreated mice, the phagocytic activity remained suppressed. Thus, it appears that slime is able to suppress the phagocytic activity of macrophages regardless of the state of macrophage activation by poly I:C. The results suggest that the inhibition of phagocytosis by S. epidermidis slime may be independent from the activation of interferon.

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The adhesive property of toxin-coregulated pilus (TCP) to the human intestine (jejunum), and whether or not TCP mediates the adhesion of Vibrio cholerae 395 organisms to the intestinal epithelium were investigated using visually proving methods. The purified TCP did not agglutinate human erythrocytes nor adhere to the surface of human intestinal epithelium. V. cholerae 395 adhered to the epithelium, but the adhesion was not inhibited by blocking the pili with the Fab fraction of anti-TCP IgG. The organisms adhered to the intestine treated with purified TCP in advance, as well as to the intact intestine. These findings suggest that TCP is not involved in the adhesion of these organisms to the intestinal epithelium.

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The effects of the lipopolysaccharide (LPS) of Proteus mirabilis on the production of thiobarbituric acid reactive substances (TBARS) and the generation of superoxide radicals (O₂^-) by pig blood platelets were studied in vitro. The effect of LPS on TBARS formation in platelets was dependent on the concentration of endotoxin. LPS at concentrations above 0.1μg/10⁸ platelets caused the production of TBARS concomitant with the generation of superoxide radicals. The responses of platelets to LPS suggest that endotoxin, like thrombin (a strong platelets agonist), stimulates an enzymatic cascade of platelet arachidonate via cyclooxygenase and produces thromboxane A₂ (TXA₂) concomitant with malonyldialdehyde (MDA).

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We attempted to detect Coxiella burnetii in dust samples collected from a barn housing dairy cattle by the polymerase chain reaction (PCR) method. Ten dust samples (five from ventilation fans and five from crossbeams) were collected from two areas in a barn on a farm near Sapporo, Hokkaido. C. burnetii was detected in 5 of the 10 dust samples. It was believed that aerial contamination by C. burnetii occurred in the barn.

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Standard guidelines for the broth microdilution antifungal susceptibility testing of amphotericin B, flucytosine, fluconazole, miconazole and itraconazole are reported. These are a modification of the method developed by the National Committee for Clinical Laboratory Standards (NCCLS) on the following two points: standardization of the means of endpoint determination and the inclusion of miconazole and itraconazole in the testing. MIC was determined to be when the positive control had a turbidity of 0.2 at the 630nm wavelength. The endpoint was 80% inhibition for azoles and 100% inhibition for other drugs. The method provided good reproducibility, and a wide range of MIC distribution was observed in all antifungal agents except amphotericin B.

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The in vitro susceptibility of Chlamydia pecorum to two macrolides (clarithromycin and erythromycin), two tetracyclines (doxycycline and minocycline), two quinolones (ofloxacin and ciprofloxacin) and one β-lactam (ampicillin) was determined. The MICs were 0.004 to 0.008μg/ml for clarithromycin, 0.008 to 0.031μg/ml for doxycycline and minocycline, 0.063 to 0.125μg/ml for erythromycin, 0.25 to 0.5μg/ml for ofloxacin and 0.25 to 1.0μg/ml for ciprofloxacin. The MIC for ampicillin was greater than 1, 024μg/ml. The results show clarithromycin and doxycycline are the two most effective drugs against C. pecorum.

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The expression of cauliflower mosaic virus (CaMV) genes was studied in a turnip protoplast system. Six CaMV-encoded gene products were detected in infected turnip protoplasts by means of Western blotting. The infected turnip protoplasts showed different patterns of protein accumulation; e.g. an open reading frame (ORF) I-encoded movement protein, an ORF V-encoded reverse transcriptase and an ORF VI-encoded posttranscriptional transactivator representing the early accumulated proteins, an ORF II-encoded aphid transmission factor and an ORF IV-encoded coat protein the late accumulated proteins and an ORF III-encoded DNA binding protein the intermediate protein. The results suggest that the expression of CaMV genes is differentially regulated.

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Two SHIVs with two or three genes deleted (SHIV-drn and SHIV-dxrn) were constructed. The inoculation of monkeys with SHIV-drn resulted in short-term viremia, but inoculation with SHIV-dxrn did not. At 68 weeks post-inoculation, the monkeys were reinoculated with a 100-fold higher dose of each SHIV, but none showed viremia. Killer cell activities against HIV-1 Env were detected in the SHIV-drn- and SHIV-dxrn-inoculated monkeys. Cross-reactive killer activity against HIV-1 Gag and SIVmac Gag was observed in one monkey. Antibodies were not detected in the SHIV-dxrn-inoculated monkeys, but the SHIV-drn-inoculated monkeys showed an anamnestic antibody reaction. These data indicate that SHIV-drn is infectious to and immuno-inducible in macaques but SHIV-dxrn is not.

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An infant born prematurely and infected with hepatitis C virus (HCV) one month after birth was followed for 4.5 years. The patient did not produce detectable anti-HCV antibodies until two years after the onset of hepatitis. Before seroconversion, a single clone of HCV, as determined by quasispecies of the hypervariable region (HVR) of the HCV genome, was almost exclusively found in the serum. After seroconversion, however, another distinct lineage of HCV clones replaced it within half a year. As HCV infection persisted further in the presence of anti-HCV antibodies, many derivatives of both sequence lineages emerged to exhibit the typical quasispecies feature of HVR sequences. Neither seroconversion nor the changes in HVR sequences influenced the serum aminotransferase titers.

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