Same adjuvanting activity was seen with another plant-produced fusion protein of the HPV16 E7; this antigen preparation was able to induce a specific CD8+ T stimulation that elicit a therapeutic affect on experimental tumours [28]. These promising results in pre-clinical models are the basis to Stem Cells antagonist undertake phase I-II clinical trials in HNSCC. Dendritic cell based Among specialized APCs the most potent are DCs because they express high levels of MHC and costimulatory molecules. Therefore on DCs were focused the research of many investigators and a variety

of methods for generating DCs, loading them with tumour antigens, and administering them to patients were developed. In fact, in murine models of HNSCC DCs, pulsed with apoptotic tumour cells and activated with interleukin-2, induced strong antigen-specific anti-tumour immunity [57]. Ex vivo loading of DCs may be achieved by proteins or peptides, or tumour cells, or genomic DNA transfection, or genetically engineered vectors,

or cell fusion techniques. By these methods a pool of uniform, controlled, and optimally activated APCs can be generated, suggesting a positive utilisation as therapeutic vaccines. Nevertheless the requirement of PS-341 clinical trial expensive GMP facilities have discouraged clinical investigators to implement phase I trials. Recent studies have shown that DC therapy produces the regression of both established carcinomas and haematologic malignancies

[58, 59]. At least three examples of DC vaccine therapy in HNSCC have been reported [5]. In the first attempt the DCs were pulsed with autologous tumour cells but the trial was interrupted because was quite impossible to obtain 107 tumour cells in sterile conditions for vaccination and the DTH evaluation PRKD3 of the patients suggested that this strategy is an unlikely candidate for large scale application. The second attempt with DCs electroporated with genomic DNA from autologous tumour cells overcame this problem and a Phase I trial is in progress. In the third attempt the DCs were loaded with sequence of wild type (wt) p53 peptides on the basis that the majority of HNSCCC over express this oncoprotein and clinical trials are underway. For the subset of HPV-related HN cancers DCs, pulsed with recombinant HPV-16 and HPV-18 E7 proteins, have been evaluated in patients with advanced HPV-associated anogenital cancers [60]. In general, the vaccine was well tolerated with no significant local or systemic side effects and HPV antigen-specific T cell responses were observed in some of the patients [61].