Koess Cordula, Hamann Joern
Department of Milk Technology and Hygiene, Institute for Food Quality and Safety, University of Veterinary Medicine Hannover, Germany.
J Dairy Res. 2008 May;75(2):225-32. doi: 10.1017/S0022029908003245.
Subclinical mastitis is a costly disease and its diagnosis is difficult. Besides the somatic cell count (SCC) and bacteriology, the differential inflammatory cell count (DICC) is a meaningful tool for mastitis detection. As microscopy is very subjective because of the low number of events to be counted, flow cytometry has often been proposed for the differentiation of milk cells. The objective of this study was to determine whether it is possible to identify subclinical mastitis in cattle at an early stage by a simple and fast flow cytometric method. The aim was to identify the main leucocyte populations in flow cytometric dotplots (polymorphonuclear neutrophils (PMN), lymphocytes and macrophages) and, with these, to elaborate a method of mastitis prognostics. Milk from 15 German Holstein cows was sampled in cross-sectional studies and SCC determined. After preparation, the milk cells were incubated with different specific antibodies that bind to different cell types and also to propidium iodide (PI), which differs between viable and non-viable cells. This procedure made it possible to localize cell types in a flow cytometric dot plot and to differentiate between viable and non-viable PMN. Percentages of viable PMN can be determined by a procedure consisting of a simple centrifugation, incubation with PI, and flow cytometric measurement. So it is possible to quickly determine the stage of the inflammation even in quarters with a low SCC.
亚临床型乳腺炎是一种代价高昂的疾病，其诊断困难。除了体细胞计数（SCC）和细菌学检查外，差异炎性细胞计数（DICC）是乳腺炎检测的一种有意义的工具。由于显微镜检查因需计数的事件数量少而非常主观，流式细胞术常被用于区分乳细胞。本研究的目的是确定是否可以通过一种简单快速的流式细胞术方法在早期识别奶牛的亚临床型乳腺炎。目的是在流式细胞仪散点图中识别主要的白细胞群体（多形核中性粒细胞（PMN）、淋巴细胞和巨噬细胞），并据此制定一种乳腺炎预后评估方法。在横断面研究中采集了15头德国荷斯坦奶牛的牛奶样本，并测定了SCC。制备后，将乳细胞与不同的特异性抗体孵育，这些抗体可结合不同的细胞类型以及碘化丙啶（PI），活细胞和死细胞对PI的摄取不同。该程序使得在流式细胞仪散点图中定位细胞类型并区分活的和死的PMN成为可能。活PMN的百分比可以通过简单的离心、与PI孵育和流式细胞仪测量的程序来确定。因此，即使在SCC较低的乳腺中，也可以快速确定炎症阶段。
