Zoonotic onchocerciasis in Hiroshima, Japan, and molecular analysis of a paraffin section of the agent for a reliable identification.

Japan is a country of high specific diversity of Onchocerca with eight species, the adults of two not yet known. Onchocerca dewittei japonica, a common filarial parasite of wild boar, had been proved to be the agent of five zoonotic onchocerciasis in Kyushu island with morphological and molecular studies. The sixth case, at Hiroshima in the main island, was identified to the same Onchocerca species, based on adult characters observed on histological sections. To consolidate the identification, mitochondrial cytochrome c oxidase subunit 1 (CO1) gene analysis was attempted with the formalin-fixed, paraffin-embedded parasite specimen. The sequence (196 bp) of a CO1 gene fragment of the parasite successfully PCR-amplified agreed well with those of O. dewittei japonica registered in GenBank, confirming the morphological identification. Moreover a comparison with the CO1 gene sequences of six other Onchocerca species in GenBank excluded the possibility that Onchocerca sp. from wild boar and Onchocerca sp. type A from cattle in Japan, were the causative agents in this case. Mitochondrial DNA analysis proved to be a valuable tool to support the morphological method for the discrimination of zoonotic Onchocerca species in a histological specimen.

[Study on the immune response of mice receiving bone allografts].

The immune response of bone allografts has not been well understood. The present study was performed to examine the MLC response, CML activity, and alloantibody production of inbred mice receiving fresh and frozen bone allografts. A) Fresh allografts: High MLC response was observed in an early phase of the culture, suggesting the activation and proliferation of helper T cells. Percent cytotoxicity of CML assay was 24% on the 9th day after grafting, indicating the production of cytotoxic T cells. High alloantibody titer was observed on the 30th day after grafting, further indicating the production of the cytotoxic alloantibody. B) Frozen allografts: No significant difference was observed between frozen allografts and fresh isografts (control group) in these immunological responses. These results indicated that the antigenicity of the frozen bone decreased greatly so that matching of the major histocompatibility complex may not be required.

Immune response to fresh meniscal allografts in mice.

To date, no study of allogeneic meniscal transplantation has investigated both the host cellular immune response and the humoral immune response. Using inbred mice, we examined cellular and humoral immunity to meniscal allografts through the mixed lymphocyte culture reaction and a complement-dependent cytotoxicity test. We also examined the histology of an allogeneic meniscus transplanted subcutaneously. The stimulation index of the mixed lymphocyte culture seen after placing fresh meniscal allografts subcutaneously was not significantly higher than when isograft controls were similarly placed. Following placement of the allografts, no specific antibodies were detected in serum throughout the 24-week period after grafting. Although viable fibrochondrocytes in the allogeneic meniscus decreased in number and lymphocyte infiltration around the allogeneic meniscus was noted at Week 2, no remarkable infiltration of lymphocytes into the meniscus was observed. These results indicate that in our experimental mouse model, a fresh meniscus apparently is not sufficiently immunogenic to induce a systemic reaction. Our results suggest that a fresh allogeneic meniscus can be transplanted without any special treatment to decrease its immunogenicity.