UR 143-INRA-URZ, Domaine Duclos, 97170 Petit-Bourg, Guadeloupe.
Vet Parasitol. 2012 May 25;186(3-4):337-43. doi: 10.1016/j.vetpar.2011.11.071. Epub 2011 Dec 6.
Small ruminants are affected by gastrointestinal nematode (GIN) infection. A promising alternative strategy for control of GIN infection is to increase the level of resistance in the population by taking advantage of the host's immune response. Immunoglobulin A (IgA) and E (IgE) are known to be involved in immune response to GIN. The aim of this study was thus to investigate genetic parameters of IgA and IgE responses against Haemonchus contortus in Creole kids naturally challenged at pasture and to determine the relationship with other resistance criteria such as faecal egg counts, packed-cell volume, eosinophil counts and bodyweight. Variance and covariance components for genetic and residuals effects for each trait were estimated on 3862 males at 11 months of age. Heritability estimates for IgA and IgE ranged between 0.15 and 0.57. Strong positive genetic correlations were observed between either IgE or IgA responses against L3 and adult excretory/secretory products (ESP) antigens of H. contortus, suggesting that the humoral immune response is not specific to the life cycle stage of the parasite suggesting that there is substantial cross recognition between the different parasite antigens. Heritability estimates for faecal egg count (FEC), packed-cell volume (PCV) and bodyweight (BW) were in accordance with previous results in Creole kids. Blood eosinophil counts were found moderately heritable and negatively correlated with FEC, suggesting that this cell population plays a role in resistance to nematode parasite infection in Creole goats. IgA response was positively correlated to FEC, in contrast with the negative correlation between IgE against L3 of H. contortus and FEC. In Creole goats, IgA response against L3 or ESP of H. contortus would rather be associated with the worm burden than an immune protective response. The immune response involving activity of IgE against L3 of H. contortus may be one important pathway for development of resistance to gastrointestinal nematode infections in Creole goats.
绵羊和山羊受到胃肠道线虫（GIN）感染的影响。利用宿主的免疫反应来提高群体的抗性水平，是控制 GIN 感染的一种很有前途的替代策略。免疫球蛋白 A（IgA）和 E（IgE）被认为参与了对 GIN 的免疫反应。因此，本研究旨在调查在放牧条件下自然感染 Haemonchus contortus 的克里奥尔幼崽对 IgA 和 IgE 反应的遗传参数，并确定其与其他抗性标准（如粪便卵计数、红细胞压积、嗜酸性粒细胞计数和体重）的关系。在 11 个月大的 3862 只雄性幼崽中，估计了每个性状的遗传和残差效应的方差和协方差分量。IgA 和 IgE 的遗传力估计值在 0.15 到 0.57 之间。针对 H. contortus 的 L3 和成虫排泄/分泌产物（ESP）抗原的 IgE 或 IgA 反应之间观察到强烈的正遗传相关性，这表明体液免疫反应不是针对寄生虫的生命周期阶段特异性的，这表明不同寄生虫抗原之间存在大量的交叉识别。粪便卵计数（FEC）、红细胞压积（PCV）和体重（BW）的遗传力估计值与克里奥尔幼崽的先前结果一致。血液嗜酸性粒细胞计数被发现具有中度遗传力，并与 FEC 呈负相关，这表明该细胞群体在克里奥尔山羊抵抗线虫寄生虫感染中发挥作用。IgA 反应与 FEC 呈正相关，与针对 H. contortus 的 L3 的 IgE 与 FEC 之间的负相关形成对比。在克里奥尔山羊中，针对 H. contortus 的 L3 或 ESP 的 IgA 反应与其蠕虫负担有关，而不是与免疫保护反应有关。针对 H. contortus 的 L3 的 IgE 反应的免疫反应可能是克里奥尔山羊对胃肠道线虫感染产生抗性的一个重要途径。
