Search for biological active molecules from tick salivary glands

为了从蜱类中获得生物活性分子，构建了长角血蜱（Haemaphysalis longicornis）半饥饿雌性唾液腺cDNA文库。随机选择克隆测序，并通过包括NCBI blastX的生物信息学程序分析总共653个序列。将序列组装成321个非冗余簇。在非冗余蛋白质数据库中同源性搜索发现，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，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管家基因。在非管家基因中，我们发现的功能注释基因有：几个蛋白酶抑制剂，两个金属蛋白酶，抗凝血酶型凝血抑制剂，以前从H. longicpornis的同源物和源自D.andersoni的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具有免疫抑制活性。这些蛋白可能在蜱虫取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.