Flow Cytometric Identification of Tumor-Infiltrating Lymphocytes from Glioblastoma.

We describe an isolation method of tumor-infiltrating lymphocytes (TILs) from glioblastoma tumors for the purpose of analysis by flow cytometry. This protocol is unique from many others in that the use of a selective lymphocyte isolation procedure, such as a Ficoll or Percoll gradient, is not used. We find that staining of TILs and analysis by flow cytometry is not affected by the presence of heterogeneous populations, while other selective isolation procedures can significantly decrease lymphocyte yield from already rare populations.