Transmission-blocking antibodies recognize microfilarial chitinase in brugian lymphatic filariasis.

Brugia malayi is a parasitic nematode that causes lymphatic filariasis in humans. The monoclonal antibody MF1, which mediates clearance of peripheral microfilaremia in a gerbil infection model, recognizes two stage-specific proteins, p70 and p75, in B. malayi microfilariae. cDNA coding for the MF1 antigen was sequenced, and the predicted protein sequence shows significant similarities to chitinases from bacteria and yeast. When microfilarial extracts and purified preparations of the MF1 antigen were tested for chitinase activity, strong bands of chitin-degrading activity comigrated in SDS/PAGE with p70 and p75 and showed a reduction-dependent mobility shift characteristic of the MF1 antigen. Thus, the MF1 antigen is microfilarial chitinase, which may function to degrade chitin-containing structures in the microfilaria or in its mosquito vector during parasite development and transmission. IMAGES:

马来布鲁线虫（Brugia malayi）是一种可引发人类淋巴丝虫病的寄生性线虫。能够在沙鼠感染模型中介导外周微丝蚴血症清除的单克隆抗体MF1（monoclonal antibody MF1），可识别马来布鲁线虫微丝蚴中的两种阶段特异性蛋白p70与p75。编码MF1抗原的互补脱氧核糖核酸（cDNA）已完成测序，其预测得到的蛋白序列与细菌和酵母来源的几丁质酶存在显著同源性。当对微丝蚴提取物及纯化的MF1抗原制剂开展几丁质酶活性检测时，强几丁质降解活性条带在十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS/PAGE）中与p70、p75共迁移，且呈现出MF1抗原特有的还原依赖性迁移位移特性。综上，MF1抗原即为微丝蚴几丁质酶，其可能在寄生虫发育与传播过程中，降解微丝蚴自身或其蚊媒体内的几丁质结构。IMAGES: