Thea D M, Pereira M E, Kotler D, Sterling C R, Keusch G T
Division of Geographic Medicine and Infectious Diseases, Tufts University School of Medicine, Boston, Massachusetts 02111.
J Parasitol. 1992 Oct;78(5):886-93.
A human-derived isolate of Cryptosporidium parvum from a symptomatic patient with the acquired immunodeficiency syndrome was expanded in vivo by infecting a neonatal calf with 10(8) oocysts. Sporozoites were isolated from 4 x 10(10) oocysts harvested from this single infection, and the characteristics of mixed hemagglutination (HA) with rabbit erythrocytes were determined. Sporozoite HA was inhibited by bovine submaxillary mucin (BSM), hog gastric mucin, and orosomucoid, but not by simple sugars, including sialic acid. Carbohydrate-inhibitable HA (lectin) activity increased with sporozoite lysis and was associated with the sporozoite membrane fractions. The ability of intact sporozoites to form rosettes around erythrocytes indicates that the HA (lectin) is, at least in part, present on the parasite surface. Hemagglutination (lectin) activity was partially purified from sporozoite lysates by affinity chromatography with BSM coupled to Sepharose-4B. Best elution was obtained with ethylene glycol and NaCl, which resulted in enrichment of 6 bands compared to the crude starting lysate (Mr = 60, 24, 22, 20, and 15 kDa and a 40-kDa doublet). Our results indicate that an HA (lectin) activity is present on the surface of intact sporozoites where it could play a role in cell-to-cell interactions with eukaryotic targets.
从一名患有获得性免疫缺陷综合征的有症状患者中分离出的人源微小隐孢子虫，通过用10(8)个卵囊感染新生小牛在体内进行扩增。从这次单一感染收获的4×10(10)个卵囊中分离出子孢子，并测定了与兔红细胞的混合血凝（HA）特性。子孢子HA被牛颌下粘蛋白（BSM）、猪胃粘蛋白和类粘蛋白抑制，但不被包括唾液酸在内的单糖抑制。碳水化合物抑制性HA（凝集素）活性随子孢子裂解而增加，并与子孢子膜组分相关。完整子孢子在红细胞周围形成花环的能力表明，HA（凝集素）至少部分存在于寄生虫表面。通过用偶联到Sepharose-4B上的BSM进行亲和层析，从子孢子裂解物中部分纯化了血凝（凝集素）活性。用乙二醇和氯化钠获得了最佳洗脱效果，与粗制起始裂解物相比，这导致6条带富集（Mr = 60、24、22、20和15 kDa以及一个40 kDa的双峰）。我们的结果表明，完整子孢子表面存在HA（凝集素）活性，它可能在与真核靶标的细胞间相互作用中发挥作用。
