Irvine M, Huima T, Prince A M, Lustigman S
Lindsley F. Kimball Research Institute, New York Blood Center, NY 10021.
Mol Biochem Parasitol. 1994 May;65(1):135-46. doi: 10.1016/0166-6851(94)90122-8.
The identification and characterization of a recombinant cDNA clone, designated OV9M, expressing an antigen present in Onchocerca volvulus infective larvae and adult stages is described. Clone OV9M was identified by screening a lambda gt11 cDNA expression library derived from adult O. volvulus mRNA using pooled rabbit antisera raised against the third (L3) and fourth (L4) stage larvae of the parasite. The cDNA clone encodes an open reading frame of 238 amino acids corresponding to a 27-kDa polypeptide. This polypeptide contains a series of five highly conserved repeats of 25 amino acids that are similar to repeats found in calponin, a protein previously only identified in vertebrate smooth muscle. Extension of the 5' end of the cDNA clone revealed two additional repeats extending the sequence to 378 amino acids, encoding a 41.8-kDa protein. Affinity purified antibodies, which bound specifically to the glutathione S-transferase-OV9M fusion polypeptide, recognize a series of antigens in extracts of O.volvulus microfilariae, L3, L4 and adult stages. The apparent molecular weight of the native OV9M protein in the adult is 45 kDa. Similar proteins are present in extracts of other nematodes including Caenorhabditis elegans, and antibodies from other filarial infections are cross reactive with glutathione S-transferase-OV9M fusion polypeptide. Immunoelectron microscopy revealed that the antigen encoded by this clone is present in the longitudinal muscles of the various larval stages and adult worms. Antibodies to the OV9M protein are present in 40-60% of both patently infected and non-patent individuals residing in onchocerciasis endemic areas.
本文描述了一个重组cDNA克隆（命名为OV9M）的鉴定和特性，该克隆表达盘尾丝虫感染性幼虫和成虫阶段存在的一种抗原。通过用针对该寄生虫第三期（L3）和第四期（L4）幼虫产生的兔抗血清混合物筛选源自成年盘尾丝虫mRNA的λgt11 cDNA表达文库，鉴定出克隆OV9M。该cDNA克隆编码一个238个氨基酸的开放阅读框，对应于一个27 kDa的多肽。该多肽包含一系列五个25个氨基酸的高度保守重复序列，类似于在钙调蛋白中发现的重复序列，钙调蛋白是一种以前仅在脊椎动物平滑肌中鉴定出的蛋白质。cDNA克隆5'端的延伸揭示了另外两个重复序列，使序列延伸至378个氨基酸，编码一个41.8 kDa的蛋白质。与谷胱甘肽S-转移酶-OV9M融合多肽特异性结合的亲和纯化抗体，可识别盘尾丝虫微丝蚴、L3、L4和成虫阶段提取物中的一系列抗原。成虫中天然OV9M蛋白的表观分子量为45 kDa。其他线虫（包括秀丽隐杆线虫）的提取物中也存在类似的蛋白质，来自其他丝虫感染的抗体与谷胱甘肽S-转移酶-OV9M融合多肽具有交叉反应性。免疫电子显微镜显示，该克隆编码的抗原存在于各个幼虫阶段和成虫的纵肌中。在盘尾丝虫病流行地区，40%-60%的显性感染个体和隐性感染个体体内都存在针对OV9M蛋白的抗体。
