A rat basophilic leukemia arose in a Wistar rat fed B-chlorethylamine and could be transplanted by subcutaneous inoculation into newborn rats (1). Because these cells (RBL-1) have been adapted for tissue culture (2–4) and have receptors for rat and mouse IgE (2–8), they have become very useful for studies of the IgE receptor (reviewed in 9) and for studies on mediators (e.g., ECFA and SRS-A) (10–13). However, these cells could not be triggered for physiologic histamine release via an IgE-mediated mechanism nor by noncytotoxic doses of compound 48/80 or the calcium ionophore A23187 (14).
Five mastocytomas were found among 99 mice of several different strains that had been treated with pristane and Abelson virus (J. G. Pumphrey, M. Potter, R. Risser and R. P. Siraganian, Manuscript in preparation). These tumors have the morphologic characteristics of mast cells, contain granules, and produce histamine and serotonin.