Fayer R, Gasbarre L, Pasquali P, Canals A, Almeria S, Zarlenga D
United States Department of Agriculture, Agricultural Research Service, Immunology and Disease Resistance Laboratory, Beltsville, MD 20705, USA.
Int J Parasitol. 1998 Jan;28(1):49-56. doi: 10.1016/s0020-7519(97)00170-7.
Twenty-six experimentally infected calves were monitored daily for oocyst excretion. All began excreting oocysts 3-6 days p.i. Most calves (n = 23) excreted oocysts for 6-9 days, with a daily range from 4 x 10(2) to 4.15 x 10(7) oocysts g(-1) of faeces. Over half the calves excreted peak numbers of oocysts 6-8 days p.i. Diarrhoea, observed intermittently beginning as early as day 3 p.i., lasted 4-16 days and varied greatly in severity from calf to calf. In a second study, nine of 18 calves were orally inoculated with 5 x 10(6) oocysts between birth and 2 days of age and nine remained uninfected. Monoclonal antibodies for cell surface markers indicated substantial increases in CD4+ and CD8+ T cells in the intraepithelial lymphocyte population of the ilea of infected calves at 7-9 days of age. RT-PCR demonstrated increases in mRNA for interleukin-12 and interferon-gamma that correlated with increases in both CD4+ and CD8 + intraepithelial lymphocyte cells. Increased mRNA for interleukin-12 and interferon-gamma from lamina propria lymphocytes correlated with increased numbers of CD8+ cells. No changes were found in interleukin-2, interleukin-4 or interleukin-10 mRNA levels. However, interleukin-15 mRNA, possibly from epithelial cells contaminating intraepithelial lymphocytes, was decreased in infected calves and had a negative correlation with increases in CD4+ and CD8+ cells. No differences were detected in mRNA levels for cytokines from lymph node lymphocytes.
对26头经实验感染的小牛每天监测卵囊排泄情况。所有小牛在感染后3 - 6天开始排泄卵囊。大多数小牛（n = 23）排泄卵囊的时间为6 - 9天，粪便中卵囊的每日排出量范围为4×10²至4.15×10⁷个/克。超过半数的小牛在感染后6 - 8天排出卵囊数量达到峰值。腹泻最早在感染后第3天开始间歇性出现，持续4 - 16天，严重程度在不同小牛之间差异很大。在第二项研究中，18头小牛中有9头在出生至2日龄之间口服接种5×10⁶个卵囊，另外9头未感染。针对细胞表面标志物的单克隆抗体显示，感染小牛在7 - 9日龄时，回肠上皮内淋巴细胞群体中的CD4⁺和CD8⁺T细胞大幅增加。逆转录聚合酶链反应（RT-PCR）表明，白细胞介素-12和干扰素-γ的信使核糖核酸（mRNA）增加，这与CD4⁺和CD8⁺上皮内淋巴细胞数量的增加相关。固有层淋巴细胞中白细胞介素-12和干扰素-γ的mRNA增加与CD8⁺细胞数量增加相关。白细胞介素-2、白细胞介素-4或白细胞介素-10的mRNA水平未发现变化。然而，感染小牛中可能来自污染上皮内淋巴细胞的上皮细胞的白细胞介素-15 mRNA减少，且与CD4⁺和CD8⁺细胞的增加呈负相关。淋巴结淋巴细胞的细胞因子mRNA水平未检测到差异。
