Hamer D H, Ward H, Tzipori S, Pereira M E, Alroy J P, Keusch G T
Department of Medicine, New England Medical Center, Tufts University School of Medicine, Boston, Massachusetts 02111.
Infect Immun. 1994 Jun;62(6):2208-13. doi: 10.1128/iai.62.6.2208-2213.1994.
The initial attachment of Cryptosporidium parvum sporozoites to host cells in vivo may be a critical event in the pathogenesis of this infection. The molecular basis of attachment and the conditions influencing this host-parasite interaction have not been studied systematically. Therefore, we have developed a sporozoite attachment model by using paraformaldehyde-fixed Madin-Darby canine kidney (MDCK) cells. Attachment of sporozoites to fixed MDCK cells was quantitated by indirect immunofluorescence and confirmed by transmission electron microscopy. Attachment in this system was time, temperature (37 degrees C), and pH (7.2 to 7.6) dependent. Dose-response studies demonstrated that the attachment of sporozoites to fixed MDCK cells was a saturable process. Attachment was enhanced in the presence of 10 mM manganese, 1 mM calcium, and 1 to 10 mM zinc. Attachment of sporozoites to MDCK cells was inhibited in a dose-dependent manner by polyclonal anti-Cryptosporidium antisera and by purified immunoglobulin G (IgG). This model will be useful for the study of parasite and host cell molecules involved in the initial interaction of C. parvum sporozoites with their target cell.
微小隐孢子虫裂殖子在体内与宿主细胞的初始附着可能是该感染发病机制中的关键事件。附着的分子基础以及影响这种宿主-寄生虫相互作用的条件尚未得到系统研究。因此，我们利用多聚甲醛固定的犬肾传代细胞（MDCK）建立了裂殖子附着模型。通过间接免疫荧光对裂殖子与固定的MDCK细胞的附着进行定量，并通过透射电子显微镜进行确认。该系统中的附着取决于时间、温度（37℃）和pH值（7.2至7.6）。剂量反应研究表明，裂殖子与固定的MDCK细胞的附着是一个饱和过程。在存在10 mM锰、1 mM钙和1至10 mM锌的情况下，附着增强。多克隆抗隐孢子虫抗血清和纯化的免疫球蛋白G（IgG）以剂量依赖的方式抑制裂殖子与MDCK细胞的附着。该模型将有助于研究参与微小隐孢子虫裂殖子与其靶细胞初始相互作用的寄生虫和宿主细胞分子。
