Search for biological active molecules from tick salivary glands

为了从硬蜱中获得生物活性分子，构建了半采食雌性长角血蜱唾液腺的cDNA文库。随机选择克隆进行测序，包括NCBI blastX在内的生物信息学软件对653个序列进行分析。这些序列被组装成321个非冗余簇。在与非冗余蛋白质数据库的同源性搜索中，约有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%的序列没有同源性。三分之二的功能可预测序列被认为是所谓的管家基因。在非看家基因中，我们发现的功能注释基因如下：几个蛋白酶抑制剂，两个金属蛋白酶，先前从长孢杆菌中鉴定的抗凝血酶类型凝血抑制物，以及安德森假丝核菌的一个同源物，预测的免疫抑制蛋白(Da-p36)。重组的Da-p36同源蛋白对牛淋巴细胞具有免疫抑制活性。这些蛋白可能在硬蜱饲养过程中发挥重要作用，有望成为新型硬蜱疫苗候选抗原。

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.