Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Ya'an 625014, China.
Parasit Vectors. 2012 Aug 16;5:176. doi: 10.1186/1756-3305-5-176.
Sarcoptic mange caused by the mite Sarcoptes scabiei is a worldwide disease affecting both humans and animals. Here we report the molecular characterization and evaluation of a recombinant S. scabiei tropomyosin (SsTm) protein in a vaccination trial in rabbits.
The full-length cDNA was cloned in a bacterial pET vector, and the recombinant protein was expressed in BL21 (DE3) cells and purified. Using specific rabbit antiserum, tropomyosin was localized immunohistochemically in mite tissue sections. Vaccination trials with the recombiant SsTm was carried out in New Zealand rabbits.
The full-length open reading frame (ORF) of the 852 bp cloned gene from S. scabiei encodes a 32.9 kDa protein. The amino acid sequence showed 98.94%, 97.89% and 98.59% homology to Dermatophagoides farina and Dermatophagoides pteronyssinus group 10 allergens and Psoroptes ovis tropomyosin, respectively. Tropomyosin was localized immunohistochemically in mite tissue sections mainly in the mouthparts, legs and integument of the epidermis. The predicted cross-reactivity of SsTm indicated that it is an allergenic protein. While vaccination with the recombiant SsTm resulted in high levels of specific IgG (P < 0.01), a low IgE antibody response and no significant protection against S. scabiei challenge were observed. After challenge, specific IgG levels remained significantly higher than the control (P < 0.01), while changes of total IgE levels were not significant (P > 0.05). However, the lesion areas in the vaccination group decreased at the end of the experiment compared with controls.
Although vaccination with recombinant SsTm did not efficiently control sarcoptic mange in rabbits, the immunogenic properties of tropomyosin suggest it may be developed as a vaccine with alternative adjuvants or delivery methods.
由螨 Scabies 引起的疥疮是一种影响人类和动物的全球性疾病。在这里，我们报告了在兔疫苗接种试验中对重组 Scabies 原肌球蛋白（SsTm）蛋白的分子特征和评估。
全长 cDNA 克隆在细菌 pET 载体中，重组蛋白在 BL21（DE3）细胞中表达并纯化。使用特异性兔抗血清，在螨组织切片中进行原肌球蛋白的免疫组织化学定位。在新西兰兔中进行重组 SsTm 的疫苗接种试验。
从 Scabies 螨克隆的全长开放阅读框（ORF）基因编码一个 32.9 kDa 的蛋白质。氨基酸序列分别与 Dermatophagoides farina 和 Dermatophagoides pteronyssinus 组 10 过敏原和 Psoroptes ovis 原肌球蛋白显示 98.94%、97.89%和 98.59%的同源性。原肌球蛋白在螨组织切片中主要在口器、腿和表皮的外皮中免疫组织化学定位。预测的 SsTm 交叉反应性表明它是一种过敏原蛋白。虽然用重组 SsTm 接种导致高水平的特异性 IgG（P < 0.01），但观察到对 S. scabiei 挑战的低 IgE 抗体反应和无显著保护作用。挑战后，特异性 IgG 水平仍明显高于对照组（P < 0.01），而总 IgE 水平的变化不显著（P > 0.05）。然而，与对照组相比，接种组的病变面积在实验结束时减少。
尽管用重组 SsTm 接种不能有效地控制兔疥疮，但原肌球蛋白的免疫原性表明它可能被开发为具有替代佐剂或给药方法的疫苗。
