The Maintenance of Tumor HLA-A2 Expression In Differing Culture Environments

Abstract

Adoptive T cell immunotherapy is an emerging field in the research of cancer treatment. Yet, despite the scientific expansion of knowledge in this area, obstacles have arisen that hinder the rapid progression of this field. Tumor cells have developed evasion mechanisms that impede effective recognition of cancerous cells by the immune system, specifically by cytotoxic T cells. The downregulation of human leukocyte antigen A2 displayed on surface major histocompatibility complex class I (MHC I) is such a tumor evasion technique. The objective of this study was to assess the maintenance of MHC I surface expression on ex vivo tumors in different cell culture media. Three tumor cell lines (one p53 gene knockout and two ex vivo) were cultured in Dulbecco's Modified Eagle Medium (DMEM) and Roswell Park Memorial Institute (RPMI) medium for eight weeks. Twice per week, the cell lines were sampled, stained, and analyzed through flow cytometry for the amount of HLA-A2 surface expression. Despite the significant amount of fluctuation and general downregulation of HLA-A2 in all three tested cell lines, the DMEM medium maintained HLA-A2 expression in a more consistent manner amongst one of the cell lines. In the future, more research should be performed to further investigate the reasons behind DMEM’s effect, as well as the mechanisms of HLA-A2 downregulation.