Search for biological active molecules from tick salivary glands

为了获得蜱的生物活性分子，从半采食的雌性长角血蜱唾液腺中构建cDNA文库。随机选择克隆进行测序，利用NCBI blastX等生物信息学程序对653个序列进行分析。这些序列被组装成321个非冗余簇。在非冗余蛋白数据库的同源性检索中，约35%的序列与已知基因有显著的相似性，提示为功能可预测基因，而其余65%的序列无同源性。三分之二的功能可预测序列被认为是所谓的家政基因。在非持家基因中，我们发现的功能注释基因如下；几种蛋白酶抑制剂，两种金属蛋白酶，抗凝血酶型凝血抑制剂，先前从长猪和安德氏d.m andersoni同源物中鉴定出预测的免疫抑制蛋白（Da-p36）。重组Da-p36同源蛋白对牛淋巴细胞有免疫抑制作用。这些蛋白可能在蜱虫摄食过程中发挥重要作用，有望成为新的蜱虫疫苗候选抗原。

To obtain biological active molecules from tick, a cDNA library was constructed from semi-fed female Haemaphysalis longicornis salivary glands. Randomly selected clones were sequenced and total of 653 sequences were analyzed by bioinformatic programs including NCBI blastX. The sequences were assembled into 321 non-redundant clusters. About 35 % of the sequences showed significant similarity to known genes in homology search against non-redundant protein database and suggested as function predictable genes whereas rest of the 65 % had no homologs. Two thirds of the function predictable sequences were suggested to be so-called house keeping genes. Among non-house keeping genes, function annotated genes which we found were as follows ; several protease inhibitors, two metalloproteases, anti-thrombin type coagulation inhibitors previously identified from H. longicpornis and a homolog of D.andersoni derived predicted immunosuppressant protein (Da-p36). Recombinant of homolog protein of Da-p36 showed an immunosuppressive activity against bovine lymphocytes. These proteins may play important roles during tick feeding and are expected to be novel tick vaccine antigen candidates.