Feline Oncornavirus-Associated Cell Membrane Antigen. I. Serologie Studies With Kittens Exposed to Cell-Free Materials From Various Feline Fibrosarcomas2

Abstract

Cell-free filtrates from 3 spontaneous feline fibrosarcomas and the Gardner-Arnstein feline sarcoma virus were each injected into 4 susceptible neonatal cats. Whole blood from a cat with a progressing sarcoma was also injected into 1 susceptible kitten. All 17 developed progressive malignant tumors. These kittens and their 4 nursing mothers were negative for antibody to the feline oncornavirus-associated cell membrane antigen (FOCMA). A fourth cell-free preparation was inoculated into 2 kittens. These kittens developed no tumors, but they and their nursing mother were positive for antibody to FOCMA. During the 23-week examination period, the 4 previously FOCMA antibody-negative nursing mothers and 4 of 5 previously negative age-matched contact controls developed detectable humoral antibody titers. This was probably due to horizontal transmission of the feline oncornavirus. Because of these findings and previous evidence that FOCMA antibody-positive dams passively transmitted antibody to their kittens which then resisted the development of malignant tumors, we recommend that contact control kittens or nursing mothers used in feline oncornavirus experiments not be returned to breeding colonies where kittens are produced for future experiments. As an additional precaution we suggest that cats of all ages used in such experiments be tested for FOCMA antibody before conclusions are drawn regarding the efficacy of any particular feline oncornavirus inoculum.