Division of Animal and Nutritional Sciences, West Virginia University, Morgantown, WV, USA.
Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA.
Parasite Immunol. 2021 Oct;43(10-11):e12876. doi: 10.1111/pim.12876. Epub 2021 Aug 21.
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.
实验性捻转血矛线虫（Hc）感染表明，特克赛尔羊的粪便虫卵计数（FEC）与抗寄生虫的圣克罗伊相似，但成虫虫荷与易感的萨福克羊相似。这些研究的目的是进一步探讨造成这种差异的机制。比较了圣克罗伊、特克赛尔和萨福克绵羊对成虫期和卵期 Hc 的细胞和体液免疫反应。将成年蠕虫和卵暴露于来自这三个品种的外周血单核细胞（PBMC）和血清中进行体外研究。用圣克罗伊和特克赛尔血清处理后，IgA 与卵的结合更强（p<.05），并且这些卵在暴露于血清和 PBMC 时孵化率更低（p<.05）。暴露于圣克罗伊和特克赛尔来源的 PBMC 和血清的成年蠕虫，其头部和生殖结构周围的结合比暴露于萨福克来源的细胞和血清的蠕虫更强。因此，卵的释放往往受品种影响（p=.09）。为了进一步研究差异，用 10000 条捻转血矛线虫 L3 感染 5 只萨福克和 5 只特克赛尔羔羊 30 天。萨福克羊每只蠕虫释放的卵多于特克赛尔羊（3.8 比 2.1 个卵/蠕虫）。综上所述，这些数据表明特克赛尔羊靶向成虫期 Hc 减少蠕虫繁殖力的机制之一。
