Lippolis John D, Reinhardt Timothy A, Goff Jesse P, Horst Ronald L
Periparturient Diseases of Cattle Research Unit, National Animal Disease Center, Ames, IA 50010, USA.
Vet Immunol Immunopathol. 2006 Sep 15;113(1-2):248-55. doi: 10.1016/j.vetimm.2006.05.004. Epub 2006 Jun 27.
Neutrophils are the first line of defense in a mammary gland infection. However, the process of neutrophil transmigration across a membrane and ingestion of fat and/or casein when incubated in milk have been shown to inhibit bacterial phagocytosis and oxidative burst functions. Recently, a killing mechanism has been described whereby stimulated neutrophils release nuclear and granule material in fibrous webs that physically trap and kill bacteria. We demonstrate that these neutrophil extracellular traps are also produced by bovine blood neutrophils stimulated with PMA/ionomycin. Importantly, neutrophil extracellular traps can be formed when neutrophils have been incubated for up to 6h in milk prior to stimulation. This contrasts milk's rapid inhibition of bacterial phagocytosis and oxidative burst functions in the neutrophil. Furthermore, stimulation of neutrophils with bacteria common to mammary gland infections leads to neutrophil extracellular traps being formed in milk. Some bacteria tested stimulated enhanced formation of neutrophil extracellular traps in milk compared to culture media. Therefore, being unaffected by incubation in milk may indicate an important role for neutrophil extracellular traps in defense against mastitis.
中性粒细胞是乳腺感染的第一道防线。然而，中性粒细胞跨膜迁移以及在牛奶中孵育时摄取脂肪和/或酪蛋白的过程已被证明会抑制细菌吞噬作用和氧化爆发功能。最近，有人描述了一种杀伤机制，即受刺激的中性粒细胞在纤维网中释放核物质和颗粒物质，从而物理性地捕获并杀死细菌。我们证明，用佛波酯/离子霉素刺激的牛血中性粒细胞也会产生这些中性粒细胞胞外诱捕网。重要的是，在刺激前，中性粒细胞在牛奶中孵育长达6小时后仍可形成中性粒细胞胞外诱捕网。这与牛奶对中性粒细胞细菌吞噬作用和氧化爆发功能的快速抑制形成对比。此外，用乳腺感染常见的细菌刺激中性粒细胞会导致在牛奶中形成中性粒细胞胞外诱捕网。与培养基相比，一些测试的细菌刺激牛奶中中性粒细胞胞外诱捕网的形成增强。因此，不受牛奶孵育的影响可能表明中性粒细胞胞外诱捕网在抵抗乳腺炎中起重要作用。
