Isolation and Immuno-Phenotypic Characterization of Tumor Infiltrating Lymphocytes (TILs) Obtained from Breast Malignant Tumor Tissues of Egyptian Patients

Background: Isolation and phenotypic characterization of tumor infiltrating lymphocytes (TILs) in some malignant tumors have been shown. TILs possess a good prognostic value as well as a therapeutic effect in these solid tumors. Our preliminary work shed some light on a good possibility of synthesis and secretion of specific protease enzyme system with a dimeric structure above 92 kDa for the lytic activity of TILs against breast tumor cells propagated ex vivo. Purpose: This work aims at first isolation, activation and immuno-phenotypic characterization of TILs derived from malignant tumor tissues of breast cancer patients. Second, to optimize the conditions for the biological therapeutic efficiency of the identified TILs sub- populations as targeted cell therapy against breast cancer. Patients and Methods: The present work presented twelve patients with breast cancer from NCI, Cairo. T- cell isolation, activation, immuno phenotyping and immunohistochemical investigations were performed. Enzymatic digestion method, mesh with pore size 355 and 45 mm and flow cytometric analysis were used. Results: The results revealed that, lymphocytes infiltrating the malignant tumor tissues were mainly of the T- cell type indicated by CD45RO positive markers as shown by immunohistochemical observations. The immuno phenotypic analysis of the isolated TILs obtained from breast tumor tissues specimens and activated with interleukin- 2 (IL-2), showed that the ratio of CD4+ /CD8+ was 0.89 which represents helper and cytotoxic sub-populations of TILs, respectively. Meanwhile, the ratio of CD4+ /CD25+ was 16.03 representing the regulatory system of TILs sub- population. In the peripheral blood of patients, the percentages of the CDs positive cells were different and the ratio of CD4+ /CD8+ was 1.14 ± 0.57 whereas the ratio of CD4+ /CD25+ was 18.38 ± 5.95. After mixing the isolated TILs and the T-lymphocytes obtained from the peripheral blood, the ratio of CD4+ /CD8+ increased insignificantly to 1.45 ± 0.67. Also the ratio of CD4+ /CD25+ increased rough insignificantly, to 23.64 ± 9.83. Conclusion: The isolated and identified TILs sub- populations have to be tested for their biological therapeutic efficacy first at ex-vivo level using the cr51 release assay; second at in-vivo level using experimental animal models as a sub-clinical investigation before going further to clinical study of using TILs as targeted bio-immunotherapy against human cancers