NY-ESO-1 is one of the most immunogenic cancer/testis antigens (CTAs) ever discovered. The immunogenicity of NY-ESO-1 mainly relies on its cross presentation in dendritic cells (DCs) to generate specific cytotoxic T lymphocyte (CTL) responses against NY-ESO-1-expressing cancer cells. Calreticulin (CRT) has been identified as a receptor for NY-ESO-1 on DC surface. CRT has been shown to efficiently bind antigens to DCs and to elicit an antigen-specific CTL response. Several receptors for CRT itself on DC surface have been reported. In this thesis, two approaches have been studied to enhance the immunogenicity of NY-ESO-1. In the first approach, the level of CRT expression on DC surface was up-regulated by calyculin A and the binding of NY-ESO-1 to DCs was increased. The function of the CT...[ Read more ]

NY-ESO-1 is one of the most immunogenic cancer/testis antigens (CTAs) ever discovered. The immunogenicity of NY-ESO-1 mainly relies on its cross presentation in dendritic cells (DCs) to generate specific cytotoxic T lymphocyte (CTL) responses against NY-ESO-1-expressing cancer cells. Calreticulin (CRT) has been identified as a receptor for NY-ESO-1 on DC surface. CRT has been shown to efficiently bind antigens to DCs and to elicit an antigen-specific CTL response. Several receptors for CRT itself on DC surface have been reported. In this thesis, two approaches have been studied to enhance the immunogenicity of NY-ESO-1. In the first approach, the level of CRT expression on DC surface was up-regulated by calyculin A and the binding of NY-ESO-1 to DCs was increased. The function of the CTLs generated from DCs pulsed with calyculin A and NY-ESO-1 protein or NY-ESO-1 protein alone was evaluated by cytotoxicity assay and CD8+ T cell activation assay. The results showed that calyculin A was able to significantly augment the specific CTL responses against NY-ESO-1-expressing cancer cells. In the second approach, the binding of NY-ESO-1 in NY-ESO-1/CRT fusion protein to DCs was found to be more efficient than NY-ESO-1 protein alone. The function of the CTLs induced by NY-ESO-1/CRT fusion protein or NY-ESO-1 protein was evaluated by cytotoxicity assay and CD8+ T cell activation assay. The results showed that NY-ESO-1/CRT fusion protein was more effective in stimulating the NY-ESO-1-specific CTL responses than NY-ESO-1 protein alone. These data demonstrate that both calyculin A and NY-ESO-1/CRT fusion protein are able to enhance the immunogenicity of NY-ESO-1. This study may provide information for developing new strategies for vaccines against NY-ESO-1-expressing cancers.