Smolenski G A, Wieliczko R J, Pryor S M, Broadhurst M K, Wheeler T T, Haigh B J
AgResearch Ltd, Ruakura Research Center, East St, Hamilton, New Zealand.
Vet Immunol Immunopathol. 2011 Sep 15;143(1-2):125-30. doi: 10.1016/j.vetimm.2011.06.034. Epub 2011 Jul 2.
Current on-farm methods for detecting mastitis in dairy cows have limitations with their specificity and sensitivity, particularly at an early stage of infection. There is therefore a need to explore new approaches for detecting early and subclinical mastitis. This study examined the expression of a group of neutrophil-specific proteins, the cathelicidins, in milk samples from naturally occurring as well as experimentally induced mastitis infections. Immunoblot analysis indicated that cathelicidin proteins are only observed in infected quarters and demonstrate a high correlation with somatic cell count (SCC) during the onset of infection. In most of the infections examined, cathelicidin was detected prior to the observation of clinical symptoms and at SCC counts as low as 6.2 × 10(3)cells/mL. In naturally occurring mastitis the correlation between cathelicidin and infection status is not as strong, with 25% of pathogen-positive milk samples containing no detectable cathelicidin. This may reflect the varying levels of neutrophil concentration and activity at different stages or severities of infection. Our results indicate that milk cathelicidin levels increase following intramammary infection and cathelicidin-based biomarkers may assist in the detection of preclinical mastitis or determining the stage of infection.
目前奶牛场检测乳腺炎的方法在特异性和敏感性方面存在局限性，尤其是在感染早期。因此，有必要探索检测早期和亚临床乳腺炎的新方法。本研究检测了一组嗜中性粒细胞特异性蛋白——cathelicidins在自然发生以及实验性诱导的乳腺炎感染的牛奶样本中的表达。免疫印迹分析表明，cathelicidin蛋白仅在受感染的乳腺中观察到，并且在感染开始时与体细胞计数（SCC）高度相关。在大多数检测的感染中，在观察到临床症状之前以及SCC计数低至6.2×10³细胞/mL时就检测到了cathelicidin。在自然发生的乳腺炎中，cathelicidin与感染状态之间的相关性不强，25%的病原体阳性牛奶样本中未检测到可检测的cathelicidin。这可能反映了在不同感染阶段或严重程度下嗜中性粒细胞浓度和活性的变化水平。我们的结果表明，乳房内感染后牛奶中cathelicidin水平会升高，基于cathelicidin的生物标志物可能有助于检测临床前乳腺炎或确定感染阶段。
