Purpose: The frequently expressed differentiation antigen tyrosinase-related protein-2 (TRP-2) has repeatedly been described as a target of spontaneous cytotoxic T-cell responses in melanoma patients, suggesting that it might be an ideal candidate antigen for T cell^based immunotherapy. As a prerequisite for immunization, T-cell epitopes have to be identified.Whereas a number of HLA class I^presented TRP-2^derived epitopes are known, information about HLA class IIp resented antigenic ligands recognized by CD4 + T helper (Th) cells is limited. Experimental Design: The search forTRP-2^derived Th epitopes was carried out by competitive in vitro peptide binding studies with predicted HLA-DRB1*0301ligands in combination with peptide and protein immunizations of HLA-DRB1*0301 transgenic mice. In vivo selected candidate epitopes were subsequently verified for their immunogenicity in humanT-cell cultures.Results: This strategy led to the characterization of TRP-2 60-74 as an HLA-DRB1*0301^restricted Th epitope. Importantly, TRP-2 60-74^r eactive human CD4 + Th cell lines, specifically recognizing target cells loaded with recombinant TRP-2 protein, could be established by repeated peptide stimulation of peripheral blood lymphocytes from several HLA-DRB1*03 + melanoma patients. Even short-term peptide stimulation of patients' peripheral blood lymphocytes showed the presence of TRP-2 60-74^r eactive T cells, suggesting that these T cells were already activated in vivo. Conclusion: Peptide TRP-2 60-74 might be a useful tool for the improvement of immunotherapy and immune monitoring of melanoma patients.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.