Biological activities of two groups of synthesized lipid A analogs, the counterpart of biosynthetic precursor, Lehmann's Ia type, 406, and E. coli lipid A type, 506, as well as their non-phosphorylated, and mono-phosphorylated analogs were investigated. The activities employed included four bone marrow cell reactions in mice, mice skin reaction, leukocytes migration in rabbits' cornea, and hemagglutination. Compound 406 and 506 elicited bone marrow reactions in mice and hemagglutination of mouse RBC, although 406 failed to elicit hemorrhage and necrosis also in mice skin. Compound 406 did not elicit corneal reaction in rabbits. The results suggest that for elicitation of this reaction and mice skin reaction, acyloxyacyl structure is required. Cytotoxicity and thromboplastin production of four bone marrow reactions had been reported by us to be endotoxic reactions, since these had not been elicited by peptidoglycan of Lactobacillus and Staphylococcus (1981) and 300 series synthetized analogs (1984) which did not have endotoxic structures. From these results, it seems that these two marrow reactions and hemagglutination require, as does the limulus test, the lipid A part structure as is present in 406.

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Pseudomonas pseudomallei exotoxin was found to be a potent inhibitor of protein and DNA synthesis in cultured macrophages. Inhibition of DNA synthesis occurred at toxin concentrations as low as 1-2μg/ml and inhibition of ³H-thymidine uptake was almost complete at concentrations of 8μg/ml or more. A close correlation between cell damage and inhibition by DNA synthesis was observed. For protein synthesis, inhibition was obtained at much lower doses (0.06-2.0μg/ml) of the toxin. At similar toxin concentrations, DNA synthesis was marginally affected. Further, it was shown that protein synthesis inhibition occurred almost immediately after incubation, reaching its maximal inhibitory effect of 70% after 6hr. DNA synthesis, however, was minimally affected by a similar toxin concentration even after 10hr of incubation. The inhibition of macromolecular synthesis in macrophages by P. pseudomallei exotoxin may be relevant to its modulatory effect on the host defense mechanism.

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Cells of Spiroplasma mirum strain SMCA were grown in PPG broth and examined by scanning electron microscopy. Comparison of the results at different time intervals allowed for a model of the life cycle of S. mirum to be proposed. Under favorable growth conditions, helical filament formation was initially observed, followed by the formation of small spherical structures originating from each filament. In old culture, large spherical bodies appeared from entangled helical filaments. From the larger spherical bodies, granular bodies representing the smallest reproductive units were produced to continue the life cycle.

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A chemotaxonomic study was carried out on Vibrio fluvialis and V. vulnificus on the basis of the sugar composition of the polysaccharide portion of their lipopolysaccharides (LPS). A previously developed rapid method of preparing samples for compositional sugar analysis was employed. Nineteen O-serogroups of V. fluvialis were divided into 14 chemotypes while seven O-serogroups of V. vulnificus were divided also into seven chemotypes since the polysaccharide portion of LPS of each serogroup has a different sugar composition from that of the other serogroups. Close similarities in the sugar composition of the same portion were demonstrated between serologically cross-reacting non-O1 group V. cholerae and V. fluvialis, and non-01 V. cholerae and V. mimicus.

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We developed a novel and convenient neutrophil adherence test for ascertaining the activated state of neutrophils. Human peripheral blood neutrophils were placed in wells of a 96-well flat-bottom culture plate, and incubated in the presence or absence of neutrophil stimulants for varying periods of time at 37C in a CO₂ incubator (5% CO₂, 95% air). After non-adherent cells were completely removed by vibration on a vortex mixer, residual adherent cells were fixed and stained with crystal violet containing 12% formaldehyde and 10% ethanol. After thorough washing, 1% SDS was added to the plate, and the absorbance of each well was measured at 570nm. Our results correlate well with those of a previously reported method using ⁵¹Cr-labeled cells.

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The effect of immunological function of GD₃ on normal bovine lymphocyte was examined with various in vitro assay systems. The GD₃ level in sera from enzootic bovine leukemia (EBL) cattle was significantly increased compared with that of normal cattle (EBL: 0.62±0.24μg/ml; normal cattle: 0.33±0.09μg/ml, P<0.05). Lymphocyte blastogenesis elicited by concanavalin A was inhibited by addition of a 50μg/ml concentration, or more, of GD₃. Inhibitory effect of GD₃ in IL-2-dependent T cell line and EBL tumor cell line was hardly observed compared with normal peripheral blood mononuclear cells. GD₃ also inhibited mixed lymphocyte reaction and allo cytotoxic T lymphocyte reaction.

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Bean golden mosaic virus (BGMV) DNA 1 and 2 have little sequence homology with maize streak virus (MSV), wheat dwarf virus (WDV), and chloris striate mosaic virus (CSMV) DNAs. BGMV DNA 1 and beet curly top virus (BCTV) DNA are closely related, whereas BGMV DNA 2 and BCTV DNA are not related. Direct amino acid homologies of predicted proteins between BGMV ORFs and MSV ORFs, WDV ORFs or CSMV ORFs were 40-50%. BGMV 1L1 and BCTV L1, and BGMV 1L3 and BCTV L4 were highly conserved. The sequence TAATATTAC was detected in the loops of hairpin structures of 5 geminiviruses.

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Serial passages in culture of herpesvirus of turkeys resulted in structural genomic changes at the regions common to two virus strains with loss of their protective ability against Marek's disease.

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Dihydroheptaprenol (DHP), a synthetic polyprenol derivative, markedly stimulated the generation of peripheral blood neutrophils after intramuscular injection in miniature pigs. The generated neutrophils exhibited enhanced phagocytic activity against latex particles and also enhanced killing activity against Escherichia coli. The effective dose in miniature pigs (1.4mg/kg) was markedly less than that required in mice (100mg/kg). These results indicate that DHP induces resistance to some bacterial infections in pigs, suggesting the applicability of DHP for humans.

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Heterohybridomas between Epstein-Barr virus-transformed human B cells and murine myeloma P3X63Ag8.653 cells were found to produce sizable quantities of human monoclonal antibodies in nude mouse ascites. Mice injected intraperitoneally with two of such heterohybridomas yielded several milliliters of ascites fluid which contained nearly 100-fold higher anti-platelet activities than those in routine culture supernatants.

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