DAMSELFISH WITH NEUROFIBROMATOSIS EXHIBIT CYTOTOXICITY TOWARD TUMOR TARGETS

Damselfish neurofibromatosis (DNF) is a malignant transmissible diseas e affecting Schwann cells, and is the only naturally occurring animal model of human neurofibromatosis type 1. The current study was designe d to determine whether fish in the early stages of disease have measur able immune responses toward DNF tumor cells. Three DNF tumor cell lin es were used as targets in standard Cr-51 cytotoxic assays. In additio n, Lutjanus griseus erythrocytes served as nonspecific targets, and co ncanavalon A (Con A) blasts from healthy animals served as normal targ et cells. Results of this study show that tumor-bearing damselfish hav e cells capable of destroying tumor targets but healthy animals displa y minimal, if any, reactivity toward the DNF tumor lines. The majority of antitumor activity resides in the spleen; the pronephros appears t o contain the majority of nonspecific activity. Data also show that so me of the effector cells are analogous to the nonspecific cytotoxic ce lls of catfish. No lysis of healthy damselfish targets was observed. T hus damselfish have cytotoxic cells capable of interacting with tumor targets, but in the majority of animals this response is not adequate to circumvent the process of tumorigenesis.