A water-soluble oligosaccharide, N-acetylchitohexaose (NACOS-6), was able to enhance the protective effect against Candida albicans infection in mice during the early phase of tumor-bearing. A significant decrease in the number of C. albicans cells in the kidneys of NACOS-6-treated tumor-bearing mice was observed 8 days after the fungal infection, or 15 days after the tumor transplantation. The candidacidal activity of polymorphonuclear leukocytes from NACOS-6-treated tumor-bearing mice did not differ from that of NACOS-6-untreated tumor-bearing mice. On the other hand, the candidacidal activities of both macrophages and T lymphocytes increased following administration of NACOS-6 in the early phase of tumor-bearing. The culture supernatant of T lymphocytes from NACOS-6-treated tumor-bearing mice also potentiated the candidacidal activity of casein-induced macrophages. An enhancement of natural killer cell activity of splenic lymphocytes obtained from NACOS-6-treated tumor-bearing mice was also observed.

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When the R-form lipopolysaccharide (LPS) from Klebsiella pneumoniae strain LEN-111 (O3-:K1-), from which cationic material had been removed by electrodialysis, was suspended in 50mM Tris buffer at pH 8.5 containing 0.1mM or higher concentrations of MgCl₂, it formed an ordered two-dimensional hexagonal lattice structure and its center-to-center distance (lattice constant) depended upon the concentration of MgCl₂ and reached the shortest value (14nm) at 10mM. In contrast, in the presence of 0.1 to 10mM CaCl₂ in place of MgCl₂, the electrodialyzed LPS did not form such an ordered hexagonal lattice structure but formed an irregular network structure with a center-to-center distance of 19 to 20nm. We investigated interaction of Mg²⁺ and Ca²⁺ in formation of the hexagonal lattice structure by the electrodialyzed LPS suspended in 50mM Tris buffer at pH 8.5. When 0.1mM or higher concentrations of CaCl₂ were mixed with 1mM MgCl₂ or when 1mM or higher concentrations of CaCl₂ was mixed with 10mM MgCl₂, the electrodialyzed LPS did not form the hexagonal lattice structure of the magnesium salt type but formed the irregular network structure of the calcium salt type. In the coexistence of equimolar or higher concentrations of CaCl₂ together with 1 or 10mM MgCl₂, the binding of Mg to the electrodialyzed LPS was significantly inhibited and, conversely, the binding of Ca was enhanced as compared with when MgCl₂ or CaCl₂ was present alone. However, the coexistence of 10 times less molar concentrations of CaCl₂ did not significantly inhibit the binding of Mg to the electrodialyzed LPS. Therefore, the inhibition of formation of the Mg²⁺-mediated hexagonal lattice structure of the electrodialyzed LPS by equimolar or higher concentrations of CaCl₂ accompanied the inhibition of binding of Mg but that by 10 times less molar concentrations of CaCl₂ did not accompany it.

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Mycoplasma salivarium (ATCC 23064) and 10 other strains isolated from human saliva agglutinated red blood cells of rabbits and human types A and O weakly, and those of sheep (SRBC) and human type B strongly. Glycoproteins on the surface of the organism cells and N-acetylneuraminic acid residues and some sugars on SRBC were suggested to be involved in agglutination of SRBC. Protein A-like activity was detected in the organism cells. The organism cells were also shown to attach to SRBC in PPLO broth (Difco) supplemented with 10% horse serum, and bivalent metal ions were suggested to be involved in the attachment. The organism cells attaching to SRBC activated complement through the alternative pathway and lyzed the SRBC.

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A year-long survey on the distribution of motile Aeromonas species in the surface waters of riverine and marine environments was conducted. The filtered membranes were directly placed onto the modified Pril-xylose-ampicillin agar for the enumeration of Aeromonas species. High counts of motile aromonads were found in riverine stations and this bacterial population was also observed in significant quantities in polluted marine samples. In the identification of 2, 444 isolates, three species of motile Aeromonas were observed. A. caviae (43%) was prevalent followed by A. sobria (35%) and A. hydrophila (20%). A. hydrophila was high in clean riverine samples, A. sobria was predominantly isolated from a stagnant water sampling area, and A. caviae was distributed more in marine samples. Statistical analyses suggested that the densities of Aeromonas were related to the cumulative effect of various physicochemical parameters rather than to a single factor. Among the species of Aeromonas, A. hydrophila, and A. sobria were highly hemolytic whereas only 11% of A. caviae were observed to lyse sheep erythrocytes. Suckling-mouse assay was performed to elucidate the enterotoxicity of motile aeromonads and 21% of the tested strains (one A. caviae strain) were found to produce enterotoxin.

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Japanese encephalitis (JE) virus was shown to grow in in vitro cultures of human monocytes. Interferon (IFN)-α and IFN-γ inhibited JE virus production by the infected monocytes in the absence of anti-JE virus antibody, but interleukin (IL)-1α, IL-2, IL-3, granulocyte-macrophage colony-stimulating factor (GM-CSF), granulocyte-CSF (G-CSF), and tumor necrosis factor (TNF)-α did not show a significant inhibition. Antibody against JE virus increased the JE virus production by the infected monocytes probably by enhanced uptake of virus-antibody complexes via Fc receptors. IFN-γ and GM-CSF increased JE virus production by monocytes in the presence of anti-JE virus antibody, whereas IFN-α inhibited JE virus production even in the presence of the antibody. The other 5 cytokines (IL-1α, IL-2, IL-3, G-CSF, and TNF-α) did not show a significant effect on JE virus production by monocytes in the presence or absence of the antibody.

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Rabbits were inoculated intracutaneously with M. salivarium (ATCC 23064) cells. The size of the resulting swelling was significantly larger in 1) the sites inoculated with viable cells (7.5×10⁹ CFU) suspended in a medium with arginine (arginine medium) than in those inoculated with killed cells, and in 2) those inoculated with cells suspended in arginine medium than with cells suspended in arginine-free medium. The swelling was enhanced when rabbits had previously been immunized with the organism. This effect was concluded to be due to ammonia which the organism produced by the hydrolysis of arginine through the arginine-dihydrolase pathway.

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Ultrathin sections of the cells of Lactobacillus casei infected with or without PL-1 phages were observed by the rapid-freezing and substitution-fixation method. Phage-head-like particles were first observed in the nuclear region. The region was seen more widely dispersed in the cytoplasm than that observed by the conventional chemical fixation method. The features of cells just broken open by the infected phages were observed by the sedimentation method devised by us. The bursting occurred in more than one place in the cells with liberation of progeny phages.

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Thy-1 antigen is anchored in the cell membrane by glycophosphatidyl inositol linkages instead of hydrophobic protein domains. The hydrophobic portion of Thy-1 antigen is cleaved by putative “transamidase.” Mutated genes were constructed by using site-directed mutagenesis. One mutant gene codes Thy-1 antigen lacking carboxy terminal amino acids from ¹¹²Cys to ¹⁴³Leu including cell membrane binding amino acid ¹¹²Cys. The other mutant gene codes Thy-1 antigen lacking from ¹²⁴Trp to ¹⁴³Leu that includes leucine core portion. DNA transfection analysis and Northern blot analysis revealed that hydrophobic portion of Thy-1 antigen is essential to express Thy-1 molecule onto the cell surface.

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