Transmission to adult pigeons of several variants of the Rous sarcoma of chickens.

Previous studies have shown that both cell suspensions and filtrates of the Rous sarcoma grown in adult chickens were entirely inactive when injected into even newborn pigeons (2). On the other hand, it was also shown that the Rous virus can be adapted to ducks and other species as well, provided the recipient host be a young or a newborn individual (1, 2) and the donor host be endowed with a certain degree of resistance linked with age (4). In the present publication, we report the fact that the Rous sarcoma after adaptation to ducks can be easily transferred to pigeons with little or no age limitations on the part of the recipient host. The duck variants of the Rous sarcoma studied were strains HV obtained in 1941 (1), 14(e), and 14(d)7 obtained in 1945 (5), and another duck tumor strain 55(e), the origin of which is rather uncertain. The pigeons employed were of the common varieties found in markets. A dditioezal attenz~pts to transfer t/ae Rous sarcoeeza to I)igeo~s. About 15 pigeons, from a few weeks to 4 months of age, were injected in the breast muscles with various amounts of cell suspension and filtrates of the Rous sarcoma from chickens of different ages. Again, no success was achieved. In one case only a tumor nodule 0.3 cm. in diameter was found in the injected site 40 days after inoculation of 2 cc. of cell suspension at 1:5. This tissue grafted into 3 more pigeons induced no growths. Str~fe~ 1 4 ( e ) . T h r e e pigeons 2 months old were injected in the muscles of each breast with 1 cc. of cell suspension of a duckling tumor of the third passage. Tumors developed which attained a sizable growth after 30 days, but regressed in 2 of the pigeons. The bird bearing the third tumor measuring by now 4 X 3 ;K 2 cm. was killed 73 days after injection and was passed by means of cell suspensions into 4 other pigeons. Growth followed in 3 with regression in 2 of them.