| Project/Area Number |
17592159
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Periodontal dentistry
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| Research Institution | NIIGATA UNIVERSITY |
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Principal Investigator |
SUGITA Noriko Niigata University, Institute of Medicine and Dentistry, Assistant, 医歯学系, 助手 (30313547)
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| Co-Investigator(Kenkyū-buntansha) |
KOBAYASHI Tetsuo Niigata University, Medical and Dental Hospital, Associate Professor, 医歯学総合病院, 助教授 (00215344)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥3,300,000 (Direct Cost: ¥3,300,000)
Fiscal Year 2006: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 2005: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | Periodontal disease / Immunology / Gene polymorphism / Pathology / Cell biology / FcγR / 抑制性レセプター / IgG |
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| Research Abstract |
Human low affinity Fc receptor IIb (FcγRIIb) is one of IgG receptors and suppress the activation of B lymphocytes through cross-linking with B cell receptor (BCR) via immune-complexes. This function of FcγRIIb is essential for the negative regulation of antibody productions. Our previous study has demonstrated the gene polymorphism FcγRIIB-I232T to be significantly associated with periodontitis. In this study, we examined the possibility that IgG antibody responses to periodontopathic bacteria Porphyromonas gingivalis (P.gingivalis) are different between periodontitis patients with different genotypes. Forty-seven patients with periodontitis were genotyped for FcγRIIB-I232T with the direct sequencing of genome DNA. Serum levels of nonspecific total IgG and specific IgG subclasses for the sonicate of P.gingivalis, the recombinant 40-kDa outer membrane protein (OMP) and 200kDa antigenic protein (AP) were determined. FcγRIIB-232T carrier revealed significantly lower IgG2 response to P.gin
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givalis 40-kDa OMP compared to noncarrier (P<0.05). Lower responses of FcγRIIB-232T carrier were also observed in specific IgG and IgG1 levels which were not statistically significant. No significant difference of antibody response to P.gingivalis sonicate or 200-kDa AP was observed between FcγRIIB-232T carrier and noncarrier. In FcγRIIB-232T noncarrier, there was a subgroup of patients showing high levels of IgG2 response in concert with the high average of probing depth. In contrast, all FcγRIIB-232T carriers revealed lower levels of IgG2 response. These results suggest that the association of FcγRIIB-232T allele with periodontitis might be attributed to the lower level of antibody response to P.gingivalis.
We investigated the expression of FcγRIIb in peripheral blood leukocytes and gingiva from periodontitis patients. Expression levels of FcγRIIb on B lymphocytes were lower in patients with periodontitis compared to controls. This might be a cause of less effective inhibition of overactivation of B lymphocytes in the pathogenesis of periodontitis. Expression of FcγRIIb was also confirmed in human gingiva with periodontitis. Less
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