In Vivo T-Lymphocyte Response Against Spontaneous Reticulum Cell Neoplasms In SJL/J Mice 1,2

ABSTRACT-The properties of lymphocytes associated with reticulum cell neoplasms (RCN) (type B) occurring spontaneously In SJL/J mice were examined. The activity of 20a-hydroxysterold dehydrogenase (20a-SDH) was used as a marker for activated T-cells. High levels of this enzyme were found In cell suspensions of tumors taken from 6- to 7-month-old mice. Treatment of the cells derived from tumorous organs with antl-8 serum and complement resulted In a loss of the 20a-SDH activity; this Indicated that T-Iymphocytes populate the RCN. The activated T-cells In the neoplastic tissue were larger than small lymphocytes. In the more advanced stage of tumor growth seen In 1-year-old mice, the percentage of malignant reticulum cells was low and the neoplastic tissue showed low levels of 20a-SDH activity. Tumor cells Irradiated In vitro triggered syngeneic lymphocytes to proliferate In tumor-lymphocyte mixed cultures. The T-cel