Perryman L E, Jasmer D P, Riggs M W, Bohnet S G, McGuire T C, Arrowood M J
Department of Microbiology, Pathology, and Parasitology, North Carolina State University, Raleigh, NC 27606, USA.
Mol Biochem Parasitol. 1996 Oct 1;80(2):137-47. doi: 10.1016/0166-6851(96)02681-3.
Two mAb, C6B6 and 7D10, each significantly reduced infection of mice by Cryptosporidium parvum and reacted with a 23-kDa glycoprotein (p23) of geographically disperse C. parvum isolates. The antibodies were used to identify plaques in a cDNA library prepared from C. parvum sporozoite mRNA. cDNA insert sequences from positive plaques were determined and used to isolate additional clones encoding p23 coding sequences. A consensus open reading frame of 333 base pairs, encoding 111 amino acids, was identified in this collection of cDNAs. The predicted amino acid sequence contained one N-glycosylation site, but lacked hydrophobic membrane spanning regions. Epitope mapping revealed that mAb 7D10 defines the linear epitope QDKPAD which occurs twice in the C terminal region of the peptide encoded by the ORF. This same C terminal peptide region contains a non-linear epitope bound by mAb C6B6. Serum from mice immunized with synthetic C terminal peptide reacted with sporozoite p23. The occurrence of neutralization-sensitive epitopes encoded by defined regions of the C. parvum genome suggests that recombinant proteins or synthetic peptides containing these epitopes may prove useful for inducing immune responses that diminish infection.
两种单克隆抗体C6B6和7D10均能显著降低小鼠受微小隐孢子虫的感染，并与地理分布广泛的微小隐孢子虫分离株的一种23 kDa糖蛋白（p23）发生反应。这些抗体被用于鉴定从微小隐孢子虫子孢子mRNA制备的cDNA文库中的噬菌斑。确定了来自阳性噬菌斑的cDNA插入序列，并用于分离编码p23编码序列的其他克隆。在该cDNA集合中鉴定出一个333个碱基对的共有开放阅读框，编码111个氨基酸。预测的氨基酸序列包含一个N-糖基化位点，但缺乏疏水跨膜区域。表位作图显示，单克隆抗体7D10确定了线性表位QDKPAD，该表位在由开放阅读框编码的肽的C末端区域出现两次。相同的C末端肽区域包含一个由单克隆抗体C6B6结合的非线性表位。用合成C末端肽免疫的小鼠血清与子孢子p23发生反应。微小隐孢子虫基因组特定区域编码的中和敏感表位的出现表明，含有这些表位的重组蛋白或合成肽可能被证明有助于诱导减少感染的免疫反应。
