Cytochemical staining characteristics of chicken heterophils and eosinophils

Cytochemistry was used to differentiate chicken heterophils and eosinophils in blood smears and cytospin preparations of isolated leukocytes. Cytochemical staining also was performed to evaluate any alteration of cell staining characteristics after heterophils had been isolated using discontinuous Ficoll-Hypaque gradients. Cytochemical staining reactions of heterophils and eosinophils were the same before and after discontinuous gradient cell separation. Characteristic positive reactions did not occur when chicken heterophils were stained with alkaline phosphatase, peroxidase, Sudan black B, acid phosphatase, alpha-naphthyl acetate esterase, naphthol AS-D chloroacetate esterase, periodic acid-Schiff, or Luna's eosinophil granule techniques. Chicken eosinophils stained positively when peroxidase, Sudan black B, acid phosphatase, and Luna methods were performed. In highly cellular cytospin preparations, peroxidase reactions readily distinguished the few contaminating eosinophils (< 1%) from the heterophils.