Gene expression and development of immunnodiagnosis for paraginimiasis using cysteine proteases from Paragonimus miyazakii

重组DNA技术越来越多地应用于寄生虫抗原的分离和鉴定。虽然半胱氨酸蛋白酶已被报道为并殖吸虫的主要抗原，但其他抗原的特征仍不清楚。利用分子生物学技术，从宫崎疟原虫成虫cDNA文库中筛选出4个组织蛋白酶L样蛋白作为抗原。本研究从宫崎疟原虫感染鼠IgG和4个半胱氨酸蛋白酶cDNA的cDNA文库中分离到3个克隆。这些克隆为1，095 - 1，552 bp，具有聚（A）尾，并且缺少它们的5'末端。这些克隆与热休克蛋白70家族，特别是热休克同源蛋白70有关。这三个克隆与细胞质热休克蛋白70同源物有关，并且没有C端内质网滞留序列KDEL序列。热休克蛋白70在蛋白质的折叠、组装、分解和降解等正常细胞过程中发挥着重要作用。热休克蛋白还在对各种寄生虫感染的免疫应答中起主要作用，即锥虫病、利什曼病、疟疾、贾第虫病、弓形虫病、丝虫病、血吸虫病、中绦虫病。热休克蛋白的一个可能作用是修复或清除由各种免疫介质引起的受损寄生虫蛋白。

Recombinant DNA technology is increasingly being applied to the isolation and identification of parasite antigens. Although cysteine protease has been reported as the major antigen of Paragonimus, characteristics of the other antigens have remained unclear. We reported four cathepsin L-like proteins as antigens from cDNA library of adult P.miyazakii using molecular biology technique. Three clones were isolated from P.miyazakii cDNA library with IgG of infected rat in addition to 4 cDNAs of cysteine protease in the present investigation. These clones were 1,095-1,552 bp with poly (A) tail and lacked their 5' ends. These clones are related to heat-shock protein 70 family, especially heat-shock cognate 70 protein. These three clones are related to cytoplasmic heat-shock protein 70 homologs and have no KDEL sequence which is C terminal endoplasmic reticulum retention sequence. Heat-shock protein 70 recent has their importance in normal cellular processes such as protein folding, assembly, disassembly and degradation. Heat-shock protein also plays a major role in the immune response to variety of parasitic infections, i.e. trypanosomiasis, leishmaniasis, malaria, giardiaisis, toxoplasmosis, filariasis, schistosomiasis, mesocestoidiasis. One possible role of heat-shock proteins is repair or removal of damaged parasite proteins caused by various immune mediators.