Stein Barry, Stover Larry, Gillem Ashley, Winters Katherine, Leet John H, Chauret Christian
Indiana University Kokomo, 2300 South Washington Street, Kokomo, Indiana 46904-9003, USA.
J Parasitol. 2006 Feb;92(1):1-9. doi: 10.1645/GE-570R.1.
The influence of lectins on Cryptosporidium parvum oocyst agglutination and on attachment to both fixed Madin Darby Canine Kidney (MDCK) cells and fixed HCT-8 (human colorectal epithelial) cells was examined. Oocyst cell wall characteristics were examined by transmission electron microscopy. Lectin-free oocysts were shown to adhere equally to both MDCK cells and HCT-8 cells. In MDCK cells, the addition of 1-25 microg/ml Codium fragile lectin, 10 microg/ml Maclura pomifera lectin, 10 microg/ml Helix pomatia lectin, and 10-200 microg/ml Artocarpus integrifolia lectin significantly increased attachment to at least 1 of the cell cultures as compared to oocysts incubated without any lectin. The lectin-enhanced attachment was reversed by co-incubation of lectin treated-oocysts with 250 mM of each specific sugar (for a given lectin). In agglutination assays, concentrations as low as 0.5 microg/ml of C. fragile, M. pomifera, and A. integrifolia lectin agglutinated oocysts within 60 min. Finally, in TEM samples, colloidal gold conjugated-lectins from A. integrifolia, C. fragile, H. pomatia, and M. pomifera attached to oocysts, and this could be competitively inhibited by a lectin-specific sugar. This suggests that C. parvum oocysts are highly reactive to N-acetyl galactosamine-binding lectins and that the presence of N-acetyl-galactosamine containing molecules on oocysts can potentially help in oocyst attachment to host cells.
研究了凝集素对微小隐孢子虫卵囊凝集以及对固定的麦迪逊-达比犬肾（MDCK）细胞和固定的HCT-8（人结肠上皮）细胞附着的影响。通过透射电子显微镜检查卵囊细胞壁特征。结果显示，无凝集素的卵囊对MDCK细胞和HCT-8细胞的附着能力相同。在MDCK细胞中，与未添加任何凝集素培养的卵囊相比，添加1 - 25微克/毫升的脆弱藻凝集素、10微克/毫升的桑橙凝集素、10微克/毫升的苹果螺凝集素以及10 - 200微克/毫升的面包果凝集素，可显著增加至少对一种细胞培养物的附着。将经凝集素处理的卵囊与每种特定糖（针对给定凝集素）的250毫摩尔共同孵育，可逆转凝集素增强的附着作用。在凝集试验中，低至0.5微克/毫升的脆弱藻、桑橙和面包果凝集素在60分钟内即可凝集卵囊。最后，在透射电子显微镜样本中，来自面包果、脆弱藻、苹果螺和桑橙的胶体金偶联凝集素附着在卵囊上，且这种附着可被凝集素特异性糖竞争性抑制。这表明微小隐孢子虫卵囊对N - 乙酰半乳糖胺结合凝集素具有高度反应性，并且卵囊上含N - 乙酰半乳糖胺分子的存在可能有助于卵囊附着于宿主细胞。
