[Observation on the phenotypic changes of tumor-infiltrating lymphocytes(TIL) during cultivation in vitro]

Tumor-infiltrating lymphocytes (TIL) were isolated from 5 malignant tumors and their phenotypes were analyzed by flow cytometry when co-cultured with recombinant human interleukin-2 (rIL-2). It was shown that 84% (+/- 8%) of TILs were OKT3+in phenotype after three weeks of cultivation. Among these, OKT8+subpopulations amounted to 77%(+/- 13%), while OKT4+subpopulations were only 14%(+/- 11), and the ratio of OKT4+/OKT8+changed from 0.5:1 (in the first week) to 0.18 (in the third week). Two parameters (mode and peak) in the histogram of flow cytometry varied in accordance with the variations of TIL's phenotypes. The results suggested that TILs stimulated by rIL-2 could be enriched predominantly in a single subpopulation (OKT8+), which might be related with their specific effects against tumor growth.