Isolation and immuno-phenotypic characterization of tumor infiltrating lymphocytes (TILs)‎ obtained from breast malignant tumor tissues of Egyptian patients

Abstract EN

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 subpopulations as targeted cell therapy against breast cancer.

Patients and Methods : The present work presented twelve patients with breast cancer from NCI, Cairo.

Tcell isolation, activation, immunophenotyping and immunohistochemical investigations were performed.

Enzymatic digestion method, mesh with pore size 355 & 45mm and flow cytometric analysis were used.

Results : The results revealed that, lymphocytes infiltrating the malignant tumor tissues were mainly of the Tcell type indicated by CD45RO positive markers as shown by immunohistochemical observations.

The immunophenotypic 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 subpopulation.

In the peripheral blood of patients, the per- centages 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 subpopulations 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.