Dosogne H, Burvenich C, van Werven T, Roets E, Noordhuizen-Stassen E N, Goddeeris B
University of Ghent, Veterinary Faculty, Department of Physiology, Biochemistry and Biometrics, Merelbeke, Belgium.
Vet Immunol Immunopathol. 1997 Dec 12;60(1-2):47-59. doi: 10.1016/s0165-2427(97)00089-5.
Phagocytosis, CD11a and CD11b adhesion receptor expression, O2-production and maturity of circulating polymorphonuclear leukocytes (PMN) were studied during acute coliform mastitis in early postpartum dairy cows to obtain a better insight in the role of neutrophils in the pathology of this disease. The mammary gland of twelve newly calved high-yielding dairy cows was experimentally infected with Escherichia coli. Variability in clinical signs of mastitis and inhibition of milk production among cows was very high. There was a significant negative correlation between the number of circulating neutrophils immediately before infection and severity of mastitis represented by the decrease in milk production of non-infected quarters two days after infection. Pre-infection phagocytosis of E. coli, CD11a and CD11b receptor expression, phorbol myristate acetate (PMA)-induced O2-production and maturity of neutrophils on a per cell basis were not related to severity of mastitis. However, significant correlations between severity of mastitis and the total number of phagocytic PMN and mature PMN in blood immediately before infection were found. PMN characteristics responded differently to mastitis depending on the severity of the disease. Neutrophil functions from cows classified as severe (S) and moderate (M) responders to infection of the mammary gland were compared. Surface expression of CD11a receptors on PMN was decreased in all cows 24 h after infection, and this decrease was long-continued in S responders. A biphasic upregulation of the number of CD11b receptors on PMN was observed with a more pronounced response in S cows. PMN phagocytosis was decreased 12 h after infection in S cows and 18 h after infection in S and M cows and was normalized 24 h post-infection. The decrease of phagocytosis coincided with the first peak of CD11b receptor expression. Phorbol myristate acetate (PMA)-induced production of O2-by PMN was decreased for three days after infection in S responders compared to only one day in M responders and was followed by an upregulation. These data demonstrate a complexity in alterations of PMN functions during mastitis and suggest the involvement of differences in systemic factors dependent on severity of mastitis.
为了更好地了解中性粒细胞在产后早期奶牛急性大肠杆菌性乳腺炎发病机制中的作用，研究了吞噬作用、CD11a和CD11b黏附受体表达、超氧阴离子（O₂）产生以及循环多形核白细胞（PMN）的成熟情况。对12头初产高产奶牛的乳腺进行了大肠杆菌实验性感染。奶牛乳腺炎临床症状和产奶量抑制的变异性非常高。感染前循环中性粒细胞数量与感染后两天未感染乳腺区产奶量下降所代表的乳腺炎严重程度之间存在显著负相关。感染前每细胞基础上大肠杆菌的吞噬作用、CD11a和CD11b受体表达、佛波酯（PMA）诱导的O₂产生以及中性粒细胞的成熟情况与乳腺炎严重程度无关。然而，发现乳腺炎严重程度与感染前血液中吞噬性PMN和成熟PMN总数之间存在显著相关性。PMN特征对乳腺炎的反应因疾病严重程度而异。比较了乳腺感染后被分类为严重（S）和中度（M）反应者的奶牛的中性粒细胞功能。感染后24小时，所有奶牛PMN上CD11a受体的表面表达均降低，并且在S反应者中这种降低持续时间较长。观察到PMN上CD11b受体数量呈双相上调，S奶牛的反应更为明显。感染后12小时，S奶牛的PMN吞噬作用降低，感染后18小时，S和M奶牛的PMN吞噬作用降低，感染后24小时恢复正常。吞噬作用的降低与CD11b受体表达的第一个峰值同时出现。与M反应者仅一天相比，感染后三天内，S反应者中PMA诱导的PMN产生O₂的能力降低，随后上调。这些数据表明乳腺炎期间PMN功能改变具有复杂性，并提示全身因素的差异与乳腺炎严重程度有关。
