Anderson L C, Rush H G, Glorioso J C
Am J Vet Res. 1984 Jun;45(6):1193-8.
The interactions of 2 capsular serotype A and 4 serotype D strains of Pasteurella multocida with rabbit polymorphonuclear neutrophils (PMN) were compared in vitro, using a PMN phagocytic and bactericidal assay. Bacteria and rabbit PMN were incubated for 15 minutes. The suspensions were subjected to differential centrifugation and the percentage of phagocytosis (cell association) was determined from the number of viable noncell-associated bacteria. The cell pellets and the associated bacteria were resuspended and PMN bactericidal activity was calculated from the number of remaining viable cell-associated bacteria at 45 and 75 minutes after the start of the assay. Test bacteria were not opsonized or were opsonized with immune serum containing active complement. One type A strain was ingested and killed by PMN in the presence and absence of opsonins. The 5 remaining strains were resistant to PMN killing, but only the type A strain resisted phagocytosis. Resistance of the type A strain was attributed to the hyaluronic acid capsule, since pretreatment of the bacteria with hyaluronidase rendered opsonized bacteria susceptible to ingestion and killing. The pattern of resistance of the 4 type D strains was different from that of the resistant type A strain. Both opsonized and nonopsonized type D bacteria became cell associated, but none were killed by PMN. The mechanism of resistance of these 4 strains to PMN bactericidal activity is currently unknown.
利用多形核中性粒细胞（PMN）吞噬和杀菌试验，在体外比较了2株多杀性巴氏杆菌A荚膜血清型菌株和4株D血清型菌株与兔PMN的相互作用。将细菌和兔PMN孵育15分钟。对悬浮液进行差速离心，并根据存活的非细胞相关细菌数量确定吞噬百分比（细胞结合率）。将细胞沉淀和相关细菌重悬，并根据试验开始后45分钟和75分钟时存活的细胞相关细菌数量计算PMN杀菌活性。试验细菌未进行调理或用含有活性补体的免疫血清进行调理。一株A血清型菌株在有或无调理素的情况下均被PMN摄取并杀死。其余5株菌株对PMN杀伤具有抗性，但只有A血清型菌株抵抗吞噬作用。A血清型菌株的抗性归因于透明质酸荚膜，因为用透明质酸酶预处理细菌可使调理后的细菌易于被摄取和杀死。4株D血清型菌株的抗性模式与抗性A血清型菌株不同。调理和未调理的D血清型细菌均与细胞结合，但均未被PMN杀死。这4株菌株对PMN杀菌活性的抗性机制目前尚不清楚。
