This study aimed to evaluate the disease severity and local immune responses in macrophage-depleted chicks with Eimeria tenella. Macrophages were reduced by intraperitoneal injection of a carrageenan solution at 12, 13, and 16 days old, whereas the control group received intraperitoneal phosphate-buffered saline. Both chick groups were orally inoculated with E. tenella sporulated oocysts at 14 days old. Feces were collected daily, which were then quantified for oocysts. The chicks were sacrificed on day 5, and the ceca were collected for histopathological observation. The gene expression levels were measured using real-time quantitative reverse transcription-polymerase chain reaction. Macrophage-depleted chicks have been observed to shed a significantly reduced number of fecal oocysts compared to the infected control group. The parasite burden score in cecum specimens of macrophage-depleted chicks was significantly lower than those of infected control on day 5 after infection. Furthermore, macrophage reduction yielded significantly lower cecum histopathological scores and CD4 expression than those of the infected control group. The expression of interleukin (IL)-18, IL-22, interferon-γ, and inducible nitric oxide synthase was also noted to be significantly upregulated in both infected control and macrophage-depleted chicks compared to uninfected chicks. IL-4, IL-13, IL-17, and perforin expressions were also higher with macrophage depletion than in both control groups. These results suggest that macrophages serve as an invasive gate or a transporting vehicle to the site of first merogony. Furthermore, mononuclear phagocytes may play an important role in local immune responses, thus contributing to parasite development during early E. tenella infection.

本研究旨在评估感染艾美球虫的巨噬细胞耗尽雏鸡的疾病严重程度和局部免疫反应。巨噬细胞在 12、13 和 16 天时通过腹腔注射角叉菜胶溶液减少，而对照组接受腹腔内磷酸盐缓冲盐水。两个小鸡组都口服接种了E.tenella14 日龄时的孢子化卵囊。每天收集粪便，然后对卵囊进行量化。第5天处死小鸡，收集盲肠用于组织病理学观察。使用实时定量逆转录聚合酶链反应测量基因表达水平。与受感染的对照组相比，已观察到去除巨噬细胞的小鸡排出的粪便卵囊数量显着减少。在感染后第 5 天，巨噬细胞耗竭小鸡的盲肠标本中的寄生虫负荷评分显着低于感染对照组。此外，巨噬细胞减少产生的盲肠组织病理学评分和 CD4 表达显着低于感染对照组。白细胞介素 (IL)-18、IL-22、干扰素-γ、与未感染的小鸡相比，诱导型一氧化氮合酶在感染的对照和巨噬细胞耗尽的小鸡中也显着上调。IL-4、IL-13、IL-17 和穿孔素的表达在巨噬细胞耗竭时也高于两个对照组。这些结果表明，巨噬细胞可作为入侵门或运输工具到第一次巨噬细胞的位置。此外，单核吞噬细胞可能在局部免疫反应中发挥重要作用，从而有助于早期寄生虫的发育。这些结果表明，巨噬细胞可作为入侵门或运输工具到第一次巨噬细胞的位置。此外，单核吞噬细胞可能在局部免疫反应中发挥重要作用，从而有助于早期寄生虫的发育。这些结果表明，巨噬细胞可作为入侵门或运输工具到第一次巨噬细胞的位置。此外，单核吞噬细胞可能在局部免疫反应中发挥重要作用，从而有助于早期寄生虫的发育。E.tenella感染。