γδ T cells in cancer

Abstract

Since the discovery of gd T cells, this rare and unique component of the immune system has been recognized for its potential in cancer immunology and immunotherapy. In the mid-1980s, it became clear that a major component of adaptive immune responses is the ability of T cell receptors (TCR) to undergo somatic recombination in order to recognize multiple antigens. TCRs consisting of either ab and gd chains were discovered in rapid succession (1–6). An important observation was made in these initial studies: gd T cells stimulated through their TCR are able to kill cancer cells (2). Over these past decades, researchers have learned that gd T cells share many similarities with ab T cells, as well as major differences. However, discoveries in gd T cell biology have failed to keep the same pace as ab T cell biology. The molecular targets of gdTCRs and functions of these cells have largely eluded researchers, partly because gd T cell recognition of cancer cells and their response kinetics are very different to ab T cells (7, 8). Recent years have seen major advances in gd T cell biology and established the non-redundancy of this lymphocyte subset, particularly in the context of cancer (9–11). gd T cells are being used as cellular vehicles to target tumors and prognostic indicators of cancer progression. The aim of the articles collected in this Research Topic is to describe new developments and approaches to enhance the anti-tumor functions of gd T cells, and to discuss how expression of their ligands can assist with prognosis of cancer patients.