A new species of lysosome in rabbit polymorphonuclear leukocytes.

A species of lysosome containing an acid hydrolase activity, i.e., acid trimetaphosphatase (TMPase) was demonstrated in rabbit polymorphonuclear leukocytes (PMNs). The lysosome was less reactive near neutral pH and non-reactive at alkaline pH. The structure appeared typically ovoid, unlike the "tubular lysosomes" reported by Oliver (J Histochem Cytochem 28:78, 1980) in several exocrine acinar cells and also observed in monocytes in this study. Neither was there Golgi activity, although there are probably few, if any, Golgi elements present in the mature neutrophil. It is interesting that the TMPase-containing lysosome occurs in an inclusion the size of a specific granule at a greater frequency than the nonspecific acid phosphatase-containing lysosome.