Studies on the mechanism of action of tumor infiltrating lymphocytes (TILs)‎ propagated ex-vivo

Abstract EN

Background : tumor-infiltrating lymphocytes (TILs) play a key role in the immunogenic reaction against tumors.

Although TILs are present in the tumor and recognize the antigenic characteristics of malignant cells, they are incapable of preventing cancer growth.

However, pre-clinical data in vitro showed that activated TILs have the ability to kill autologous tumor cells.

As a result, a number of clinical reinfusion trials using interleukin-2 (IL-2) - activated TILs have been conducted in the past few years.

Purpose : the therapeutic efficiency of TILs is not clearly understood, as only few studies have been performed on a limited number of patients and therefore this work aims at studying the mode of action of TILs propagated Ex vivo through investigating protease enzyme system using SDS-PAGE of gelatin zymography technique.

Material and methods : In this work, TILs as well as peripheral blood lymphocytes (PBL) were separated from patients suffering from breast cancer.

Primary culture of TILs, PL as well as tumor cells were performed.

A co-cultivation of TILs and tumor cells in the presence of IL-2 was done.

Gelatin zymographic analysis using polyacrylamide gel electrophoresis of the protease enzyme system was performed.

Results : the work done revealed that: aggregation of TILs around tumor cells was clearly observed when a mixed culture of both TILs and tumor cells was co-cultivated in vitro.

At a molecular level, there were two separate clear and sharp bands at approximately 72 and 92 kDa seen in gelatin zymography.

The bands were much clearer with an extra band with diametric structure above 92 kDa in cell lysate of the mixed culture of both TILs with tumor cells as well as their conditioned media.

Conclusion : the study findings may shed some light on a good possibility of synthesis and secretion of specific protease enzyme system for the lytic activity of TILs against tumor cells.

Further work is strongly recommended for identification of the extra band produced due to the TILs and tumor cells interaction in addition to the possible specific novel therapy of TILs in cancer management.