The blood leukocytes of Bufo alvarius: a light, phase-contrast, and histochemical study

Abstract

Blood leukocytes of Bufo alvarius were studied by light and phase-contrast microscopy and histochemical techniques for the localization of glycogen and several hydrolytic enzymes, i.e., acid and alkaline phosphatases, nonspecific esterase, beta-glucuronidase, aryl-sulfatase, and myeloperoxidase (peroxidase). Neutrophils were the only leukocytes to demonstrate alkaline phosphatase activity, while beta-glucuronidase and aryl-sulfatase were not observed in any leukocytes. Periodic acid – Schiff (PAS) positive granules and granules containing hydrolytic enzymes occurred in varying amounts in leukocytes. In eosinophils, most glycogen was associated with smaller granules, while the larger refractile granules were PAS negative. Small lymphocytes were myeloperoxidase (peroxidase) negative. The present study agrees with previous investigations in mammals which indicate that specific granules in granulocytes may be PAS positive as well as contain one or more hydrolytic enzymes. In small lymphocytes of B. alvarius, PAS positive and acid phosphatase positive granules correspond to neutral red granules seen in supravital films. Furthermore, the appearance and histochemical reactivity of acid phosphatase granules in mature neutrophils, metamyelocytes, and late myelocytes correspond closely with the appearance and number of specific neutrophilic granules seen in Wright–Giemsa preparations and with PAS positive granules.