Methods for evaluation of the adhesive and phagocytic capacities of porcine granulocytes

The adhesive and phagocytic properties of porcine neutrophils were studied. Blood samples were collected from healthy crossbreed pigs, and granulocytes were obtained by density centrifugation. Adhesion to nylon wool was studied and expression of adhesion molecules was determined by flow cytometry. Three monoclonal antibodies showed reactivity with porcine cells and were thus subsequently used. Freezing and storage at -70 degrees C did not cause major alterations in the expression of adhesion molecules. The kinetics of phagocytosis of serum- and IgG-opsonized yeast cells were studied with fluorescence microscopy and flow cytometry. The influence of various concentrations of normal pooled and heat-inactivated pooled porcine serum on the phagocytic process was elucidated. The phagocytic process was completed more rapidly using C3b- than IgG-opsonized yeast cells. The neutrophils both attached to and ingested the serum-opsonized yeast cells to a large extent. When IgG or heat-inactivated serum were used, only minor attachment was observed. These methods for studies of neutrophil functions can be used both for the diagnosis of immunological disorders and for physiological studies of the neutrophil functions in the pig.