The Propagation of Filtrable Agents Producing Lymphoid Tumors And Osteopetrosis by Serial Passage in Chickens

Although numerous experiments have shown that erythroand myeloid leukosis may be transmit ted by a filtrable agent (14), only a few reports have suggested tha t lymphomatosis may be transmit ted by a similar agent. By the use of filtrates of strain 2, Fur th (9) produced what was thought to be a rare type of lymphomatosis. I t was characterized by the appearance, in the blood and many organs, of large lymphocytes with occasional formation of lymphoid tumor-like nodules, endothelioma and severe anemia. Pentimalli (16) described a readily transplantable lymphoid tumor strain. Based upon results obtained from filtration, desiccation, and glycerination experiments, he concluded that the strain did not contain a filtrable agent. Olson (15) developed a tumor strain having similar characteristics; however, he did not report on a t tempts to transmit it by cell-free material. The propagation of 4 lymphoid tumor strains by cell transplantat ion from cases of natural ly occurring visceral lymphomatosis was reported by Burmester and Prickett (3). These strains were similar among themselves and to those of Pentimalli (16) and Olson (15) in that the type of involvement was similar, the incidence of tumor takes was high and the rate of tumor growth was rapid. Brewer and Brownstein (2) have also reported on the rapid transmission of visceral lymphomatosis with suspensions of tumor pulp. Burmester, Prickett , and Belding (4) in a series of 3 experiments demonstrated the presence of a filtrable agent in the lymphoid tumor originally studied by Olson (15) and obtained at this Laboratory in June, 1942 and since designated here as R P L 12. This filtrable agent failed to induce tumors at the site of inoculation in a short period of time (inocula-containing cells produce tumors ,at the site of inoculation) but produced within 6 months' time a high incidence of osteopetrosis and lymphomatous tumors of the viscera. The object of this paper is to report on the propagation of the filtrable agents of the lymphoid tumor strain RPL 12 during 6 serial passages in young chickens and to describe the gross manifestations obtained in the various passages, with different routes of inoculation, and with different types of donors and preparations.