[Separation and functional analysis of tumor-infiltrating lymphocytes in brain tumor tissues].

Separation of tumor-infiltrating lymphocytes (TIL) from surgical specimen of fourteen gliomas and 6 metastatic brain tumor tissues was achieved by discontinuous density gradients. Comparison of phenotypes between separated lymphocytes and TIL in situ was examined by immunohistochemical method using monoclonal antibodies. The cytotoxic activity of these separated lymphocytes was also examined in short-term 51Cr release assay against fresh autologous tumor cells. Immunohistochemical staining of separated lymphocytes revealed the preservation of cell surface antigens of the lymphocytes. Most of separated lymphocytes were T lymphocytes and both phenotypes cytotoxic/suppressor and helper/inducer T lymphocytes were found. The Leu-3a/2a ratio of separated lymphocytes were compared with TIL in situ in the same patients and these values were almost equal in both lymphocytes. Cell number of separated lymphocytes were 1.2 x 10(5)-2.1 x 10(5)/g in glioma and 1.1 x 10(5)-3.8 x 10(5)/g in metastatic patients. Cytotoxicity against autologous tumor cells was detected in 5 out of 12 glioma and 2 out of 6 metastatic patients. There was no correlation between the cytotoxicity and cell number of separated lymphocytes or HLA-DR antigen expression on tumor cells.