The Antitumor Effect of Interferon in Lymphocyte- and Macrophage-Depressed Mice

Abstract

Summary

The antitumor effect of interferon was assayed in mice pretreated with ALS to depress lymphocytes or with silica to depress macrophages. Pretreated DBA/2 mice were inoculated intraperitoneally with interferon-sensitive or interferon-resistant L 1210 cells, and Balb/c mice were inoculated intraperitoneally with Ehrlich ascites cells. The efficacy of interferon was determined by its effect either on survival time in L 1210 tumor-inoculated mice, or on the multiplication of EA cells. Interferon proved as effective in ALS-pretreated tumor-inoculated mice as in mice not receiving ALS. Pretreatment of mice with silica diminished somewhat, but did not abolish the antitumor effect. It is concluded that interferon can exert an antitumor effect in lymphocyte-and macrophagedepressed mice.

One of us (I.G.) is indebted to Dr. Sidney Farber, Director of the Childrens Cancer Research Foundation, Boston, Mass., for his continued interest and support.

We are grateful to Dr. A. C. Allison for his advice in the experiments on silica, to Drs. A. C. Allison and K. Roböck for their generous gifts of silica, and to Dr. Pernilla Lindahl for many helpful discussions.