Chemotaxis of fowl monocytes to Pasteurella multocida and associated antigens

The interaction of monocytes and serum from Pasteurella multocida-immunized and non-immunized turkeys and chickens was studied for their chemotactic activity to lipopolysaccharide, free endotoxin, and P. multocida whole cells. Chemotactic factors were released from the interaction between either normal sera or antisera and the bacterial antigens. Heating of the sera affected their ability to interact and release chemotaxins. Heated normal sera were ineffective and heated antisera were less effective than unheated sera. Monocytes collected from immunized and non-immunized fowls responded to the chemotactic factors. This occurrence of heat-labile and heat-stable chemotaxigens in the sera suggests that antibody and complement are involved in the stimulation of chemotaxis.