Human gamma delta T cells: a nonredundant system in the immune-surveillance against cancer

Down-regulation of expression of MHC alleles, as well as tumor-specific antigens, is observed frequently during tumor progression, resulting in an impairment of MHC-restricted, alphabeta-T-cell-mediated, tumor-specific immunity. Given the unique set of antigens recognized and the lack of requirement for classical antigen-presenting molecules, gammadeltaT cells might, therefore, represent a nonredundant system in anticancer surveillance, as proposed for the immune response against pathogens. Evidence that gammadelta and alphabetaT cells make distinct contributions to anticancer surveillance has been provided recently in mice. Here, we discuss the potential role played by resident Vdelta1(+) and circulating Vdelta2(+) T cells in the defense against solid tumors and hematological malignancies.