Analyses of tumour-infiltrating lymphocytes revealed a greater percentage of Treg in HNSCC compared with the circulating counterpart of both patient and healthy controls , suggesting that in HNSCC Treg cells are recruited in the tumour area respect to the lymphnode or circulating location. Recently, it has been reported that naïve antigen-specific T cells can be either activated or tolerized simultaneously in the same host, depending on the microenvironment in which the epitope is Selleck ATM Kinase Inhibitor presented . Effector T cells generated in lymph nodes
are tolerized rapidly when they infiltrate antigen-expressing learn more tumour tissues. Interestingly, tolerant T cells persist only in the tumours and resemble tumour infiltrating lymphocytes seen in cancer
patients . In the clinical setting the effect of Treg may be attenuated by depleting them with non-myeloablative chemotherapy or monoclonal antibodies against inhibitory receptors (anti-CTL antigen-4 [CTLA4]) [15, 16]. In various mouse models antibodies against the glucocorticoid-induced tumour necrosis factor receptor family (GITR) are able to downregulate Treg functions increasing the efficacy of immunotherapies [17, 18] However the role of the human counterpart of this receptor huGITR appears to be quite different with less activity on Treg suppression [19, 20] Controlled and effective modulation of Treg check details cell function for cancer therapeutics will be contingent on a better understanding of the molecular basis of Treg cell interaction with tumour cells and ensuing immunosuppressive mechanisms. A study using a synthetic monoclonal antibody targeted against CD28 met with disastrous results, reminding us that manipulation of costimulatory/regulatory pathways requires more information in this field . Nevertheless continuing investigation on the biology of Treg in antitumour immunity Temsirolimus solubility dmso and potential toxicities of Treg suppression will undoubtedly implement the efficacy of cancer immunotherapies. Finally in patients with HNSCC the absolute number of T-lymphocytes
both CD4+ and CD8+ is reduced and it may be related with a decrease expression of chemokine receptor 7 (CCR7) on T cells . CCR7 has been implicated in protecting CD8+ T cells from apoptotic cell death. Indeed CD8+ CCR7-negative T lymphocytes that are more sensitive to apoptosis were increased in HNSCC patient peripheral blood compared with healthy controls . These are the major barriers that have to be broken by an effective therapeutic vaccine. Before reaching the tolerance or tumour escape a therapeutic vaccine must elicit a strong cellular immune response involving the CD4 and CD8 stimulation. Many strategies have been developed to induce a response against the TAA. In particular the HPV E7 antigen has been utilised to develop an incredible large number of different possible therapeutic vaccines extensively reviewed elsewhere .