CHARACTERIZATION OF TUMOR-INFILTRATING LYMPHOCYTES FROM MURINE MAMMARY ADENOCARCINOMAS

The aim of this investigation was to assess the in vitro functional an d phenotypic characteristics of lymphocytes isolated from C3H mouse ma mmary adenocarcinomas. A protocol was developed for the expansion of T ILs in long-term culture. The homing pattern of TILs prepared and grow n in this manner was studied. Cells that had been in culture for up to 96 days accumulated at higher levels in mammary tumors than in corres ponding normal mammary tissue 24 hr after adoptive transfer. The abili ty of cultured TILs to lyse YAC-1 cells was determined. Peak activity was demonstrated by lymphocytes that had been in culture for three day s. By two weeks in culture the level of cytotoxicity returned to that of fresh TILs, and after 45 days it was negligible. T cells were the m ajor constituents in all preparations. The relative frequency of CD8cells remained fairly constant over time in culture, but that of CD4cells declined. At all time points the CD4:CD8 ratio for TILs was less than 1. The percentage of ASGM(1) + bright cells among fresh TILs was low. It increased dramatically within 3 days, remained high for about 7 weeks, and then declined rapidly to pre-culture levels. An unusual large cell characterized by the presence of an intensely PAS positive peripheral region was observed.