1988 Fiscal Year Final Research Report Summary
Studies on immunology and molecular biology of host-parasite interactions
| Project/Area Number |
61304037
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| Research Category |
Grant-in-Aid for Co-operative Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
寄生虫学(含医用動物学）
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| Research Institution | Chiba University |
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Principal Investigator |
KOJIMA Somei Chiba University School of Medicine, 医学部, 教授 (00009622)
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| Co-Investigator(Kenkyū-buntansha) |
WATANABE Naohiro Jikei University School of Medicine, 助教授 (00057019)
SENDO Fujiro Yamagata University School of Medicine, 医学部, 教授 (80091833)
YOSHIMURA Kentaro Akita University School of Medicine, 医学部, 教授 (90053058)
SUGANE Kazuo Shinshu University School of Medicine, 医学部, 教授 (50112488)
TANABE Kazuyuki Osaka City University School of Medicine, 医学部, 助手 (40047410)
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| Project Period (FY) |
1986 – 1988
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| Keywords | Host-parasite relationship / antigenic variation / parasite antigen genes / monoclonal IgE / protective immunity / 免疫変調 |
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| Research Abstract |
To better understand host-parasite interactions, immunological studies were carried out on cellular and molecular levels. 1) Adaptation of protozoan parasites in hosts and their antigenic variation: Plasmodium falciparum was found to poliferate in human eryhrocytes without being affected by levels of Ma^+ or K^+, although the parasite died easily by treatment with Ca^<2+> modulators. A 25kDa molecule was found to be specific to all stages of trypanosoma cruzi, while antigcnic variation of T.gambiense occurred in vitro in the abscence of monoclonal antibodies about 100 times more frequently than in vivo. 2) Analysis and gene cloning of parasite antigens: The complete nucleotide sequence of a surface antigen (p190) of P.falciparum merozoites was determined and comparisons of the gene from various strains revealed that the p190 gene consisted of several blocks of conserved, semi-conserved and variable sequneces, the last of which were not widely polymorphic but fell into two types. Using
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mRNA of Trichinella spiralis larvae, 97% of cDNA coding an antigenic molecule of 48kDa was obtained. A mouse monoclonal IgE antibody was prepared against a 97kDa surface molecule of Schistosoma iaponicum. Results of chemical analysis suggested that the molecule was a glycoprotein containing a complex of sugar chains bound to asparagine. 3) Disturbance of host immune mechanisms by parasitic infections: Increase of OKT4- and OKla-1- positive cells was observed in patients with strongyloidiasis in association with decrease of OKT8-positive cells. Proliferative responses of lymphocytes to mitogens significantly reduced in these patients if compared to the responses in parasite-free controls. Schistosome infections lead to reduction in IL-2 production and responsiveness to IL-1 and IL-2, in addition to polyclonal b cell activation. It was also suggested that eosinophils had receptors to chemotactic factors derived from young adult worms or first stage larvae of Angiostrongylus cantonensis. Furthermore, IgE-bearing B cells increased in number after helminth infections in association with increase of quanitity of the surface IgE. Less
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