Observations on the Blood of the Australian Lungfish, Neoceratodus-Forsteri Klefft .2. Enzyme Cytochemistry of Blood-Cells, Peritoneal-Macrophages and Melanomacrophages

Abstract

Peroxidase, alkaline and acid phosphatases, esterases, neutral proteases and PAS reactivity were examined in the peripheral blood leucocytes and peritoneal and melano-macrophages of the Australian lungfish. Eosinophils contained partly cyanide-inhibited peroxidase, and monocytes and blasts showed weak peroxidase staining, but other blood leucocytes were negative. Only neutrophils and heterophils showed alkaline phosphatase reactivity, but acid phosphatase was ubiquitous in leucocytes and macrophages. Alpha-naphthyl acetate esterase and naphthol AS-D chloroacetate esterase occurred, and were often strong, in all cell types but particularly neutrophils; alpha-naphthyl butyrate esterase was only observed in monocytes, macrophages, and in the latter stained moderately to strongly. Beta-glucuronidase, beta-galactosidase and N-acetyl-beta-glucosaminidase were also confined to the monocyte/macrophage lineage. The neutral protease acetyl-L-tyrosine-a-naphthyl esterase was moderate to strong in monocytes and macrophages. All leucocytes except monocytes stained moderately to strongly by PAS. Leucocytes showed similarities in enzyme content to those of elasmobranchs, but less so to those of teleosts. They also resembled leucocytes of mammals, particularly in monocyte-macrophage enzyme profiles, in the heterogeneous response for peroxidase, and the restriction of a-naphthyl butyrate esterase to that lineage.