ANTITUMOR AGENTS ON THE PRODUCTION OF PRIMARY AND SECONDARY SPLEEN HEMOLYSIN PLAQUE-FORMING CELLS

¹ Department of Pharmacology, University of Kansas Medical Center, Kansas City, Kansas

A study was made on the action of cyclophosphamide (CY), amethopterin (MTX), 6-mercaptopurine (6 MP) and vinblastine (VBL) to alter the production of primary and secondary hemolysin plaque-forming cells (HPFC) arising in the spleens of LAF mice injected with sheep red cells. A single injection of sheep red cell antigen within the 2-week period of observation favors the development of secondary or 7s HPFC. In animals injected with CY, MTX or VBL, the numbers of secondary HPFC were lowered to values significantly below controls. Only CY-treated animals showed a decrease in primary or 19s HPFC. A second injection of sheep red cells within the 14-day period favors the development of primary HPFC. With this regimen, injection of CY and VBL significantly lowered both primary and secondary HPFC, whereas MTX-and 6 MP-treated animals were not affected. The effects of various treatments on spleen cellularity and serum hemolysin titers are also discussed.