Stimulation of non-opsonic phagocytosis in avian respiratory phagocytes

Avian respiratory disease costs the U. S. poultry industry millions of dollars per year in lost production. The avian respiratory system, while similar in many ways, differs from that of mammals anatomically, physiologically, and in its response to invasion by infectious agents. One of the least understood components is the variety of cell types collectively referred to as avian respiratory phagocytes (ARP), the first line of defense against invasion. The resident ARP population is normally very low, but numbers increase in response to certain stimuli. We undertook a study to quantify the extent of ARP influx and the degree of increase in phagocytic activity in response to the presence of non-pathogenic Pasteurella multocida. Chickens were stimulated by intratracheal inoculation of P. multocida, and the ARP's collected by lavage of the lungs and air sacs. Control birds were inoculated with vehicle carrying no P. multocida, and then lavaged.