Bovine peripheral blood polymorphonuclear neutrophil chemotactic response to Pasteurella haemolytica or...

The chemotactic influence of Pasteurella haemolytica and of products of its growth was evaluated in vitro, using bovine peripheral blood polymorphonuclear neutrophils (PMN) in an underagarose migration assay system. Pasteurella haemolytica was cultured, quantitated, killed, and lysed by freeze-thawing. The PMN directional migration toward P haemolytica lysate was not significantly (P less than 0.9) different from spontaneous random PMN migration. Also, there was no chemotactic effect of viable 6-hour cultures of P haemolytica when tested in the in vitro underagarose system. Directional migration (1.70 +/- 0.53 mm) of PMN to zymosan-activated pooled bovine serum was observed and determined to be significantly (P less than 0.001) greater than was spontaneous random PMN migration (0.84 +/- 0.21 mm).