Experimental Haemonchus contortus (Hc) infections revealed that Texel sheep have faecal egg counts (FEC) comparable to parasite-resistant St. Croix but adult worm burden comparable to parasite-susceptible Suffolk sheep. The aim of these studies was to further investigate the mechanism causing this disparity. Cellular and humoral immune responses to adult- and egg stage Hc were compared amongst St. Croix, Texel and Suffolk sheep. Adult worms and eggs were exposed to peripheral blood mononuclear cells (PBMC) and serum from the three breeds in vitro. There was a greater IgA binding to eggs when treated with St. Croix and Texel serum (p < .05), and these eggs exhibited a lower hatch rate (p < .05) when exposed to serum and PBMC. Adult worms exposed to St. Croix and Texel-derived PBMC, and serum had greater binding around the head and reproductive structures than worms exposed to Suffolk-derived cells and serum. Consequently, egg release tended to be affected by breed (p = .09). To further examine differences, Suffolk and Texel lambs (n = 5/breed) were infected with 10,000 Hc L3 for 30 days. Suffolk sheep had greater egg release per worm than Texel (3.8 vs. 2.1 eggs/worm). Taken together, these data would indicate one of the mechanisms in Texel's targeting adult-stage Hc reducing worm fecundity.

中文翻译：

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Texel绵羊对捻转血矛线虫成虫和卵期的免疫机制

实验性Haemonchus contortus ( Hc)感染表明，Texel 绵羊的粪便卵数 (FEC) 与抗寄生虫的 St. Croix 相当，但成年蠕虫的负担与对寄生虫易感的 Suffolk 绵羊相当。这些研究的目的是进一步调查造成这种差异的机制。比较圣克罗伊、特塞尔和萨福克绵羊对成体和卵期Hc 的细胞和体液免疫反应。成虫和卵在体外暴露于来自三个品种的外周血单核细胞 (PBMC) 和血清。当用 St. Croix 和 Texel 血清处理时，IgA 与鸡蛋的结合更强 ( p  < .05)，这些鸡蛋的孵化率较低 ( p < .05) 当暴露于血清和 PBMC 时。与暴露于 Suffolk 衍生细胞和血清的蠕虫相比，暴露于 St. Croix 和 Texel 衍生的 PBMC 和血清的成虫在头部和生殖结构周围具有更大的结合。因此，产蛋量往往受到品种的影响 ( p  = .09)。为了进一步检查差异，Suffolk 和 Texel 羔羊（n  = 5/品种）用 10,000 Hc L3感染30 天。与 Texel 相比，萨福克绵羊每条蠕虫的卵释放量更高（3.8 对 2.1 卵/蠕虫）。综上所述，这些数据将表明 Texel 靶向成年期Hc降低蠕虫繁殖力的机制之一。