アクティブボード・２０１０年１２月
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研究発表を行った学会；
・第１１回熊本エイズセミナー・グローバルCOE合同国際シンポジウム
　２０１０年１０月６日（水）〜８日（金）

タイトル；Evolution and selection of the env gene of HIV-1 primary isolates during in vitro selection of raltegravir.
　
発表者；　原田　惠嘉　氏
　　　（熊本大学　エイズ学研究センター　吉村プロジェクト研究室）

Abstract；
　Although the aim of our study is to generate raltegravir (RAL)-resistant viruses by serial passage with recently isolated HIV-1s, we did not generate highly RAL-resistant variants yet. Unexpectedly, the separation of Env sequences between RAL-selected and control passaged viruses during the in vitro selection of RAL was observed. To investigate the curious finding we determined the amino acid sequence of both integrase (IN) and gp120-encoding regions of each passaged variants cultured with RAL, and also analyzed the sensitivity of the variants to RAL and entry inhibitors using a single- and multi-round assay.
In phylogenetic analysis, Env sequences of all RAL-selected primary isolates (from PI-1 to PI-5) were completely distinct from those of the same passaged control viruses. The both Env sequences were existent in the baseline viruses for quasi-species. This finding suggests that the mixture viruses with distinct sequences in the Env region were affected for the adaptation to the target cells under the pressure of RAL. Moreover, the maraviroc (MVC)-resistant PI-1 variant (PI-1/MVC, CRF08_BC) was sensitive to RAL compared to the same passaged control, however, no other additional mutations were observed in the IN region. Thus, we started to try to generate RAL-resistant variant using the MVC-resistant virus PI-1/MVC.
Interestingly, at 8 passages the RAL-selected PI-1/MVC variant became highly sensitive to MVC compared to the baseline virus because the 8-passaged variant acquired one amino acid substitution, Pro to Leu at position 313 (P313L, 10 of 10 clones) in a tip of V3 of gp120. This result also suggests that in the presence of RAL these variants exert a selective pressure on the Env region.
In conclusion, our present study suggests that the mixture of viruses with distinct sequences in Env region was affected for the cell adaptation under the pressure of RAL. These finding data may give important knowledge for combination of RAL therapy in the future.