ARYLSULFATASE-B IN KURLOFF CELLS - INCREASED ACTIVITY OF ANIONIC ISOFORMS IN GUINEA-PIG ACUTE LYMPHOBLASTIC-LEUKEMIA

We examined the in vivo role of Kurloff cells (KC), guinea pig natural killer cells, during the development of L2C leukemia, by analysing ch anges in the arylsulfatases (Asases) in the lysosomal Kurloff body. Th e Kurloff body is rich in acid phosphatase, esterase and proteoglycans , as are large granular lymphocyte granules. Moreover, the Kurloff bod y contains lysosomal Asase B, with unusual anionic isoforms. Injection of L2C cells elicited a three-fold increase in KC Asase activity on d ay 6. The increase in KC Asase activity was correlated with the number of circulating L2C cells. The basic Asase form (pl 8) was lost, and a concomitant increase in anionic isoforms (pl 5-6) was observed on day 6. The role of the latter in cytolysis was investigated by examining their capacity to lyse L2C target cells. We conclude that Asase partic ipates in cytolysis when lysis is mediated by the complete assembly of cytolytic proteins. Changing and increasing KC Asase activity during leukemia development may be a marker for activated KC in vivo. These f indings suggest that the cytolytic activation of KC occurs during the preleukemic period. Copyright (C) 1996 Elsevier Science Ltd.