Abstract: The present invention relates to methods for enhancing exogenous epitope display on an MHC class I molecule through inhibition of TAP activity. Mammalian cell-infecting virus vectors encoding both a TAP inhibitory factor and an epitope-linked-?2m were constructed and introduced into mammalian cells. The present inventors succeeded in displaying on the cell surface in high frequency the MHC class I/peptide complex containing an epitope-linked-?2m expressed from the vector by reducing endogenous MHC class I/peptide complexes by the action of the TAP inhibitory factor. The present invention finds utility in vaccine therapies for infectious diseases, cancers, and the like.

Abstract: A &lgr; phage with a nuclear localization signal has been obtained by constructing a vector capable of expressing a fused protein between a gpD protein constituting the head of a &lgr; phage and a nuclear localization signal sequence, transforming Escherichia coli with this vector, and propagating a mutant &lgr; phage which cannot express the gpD protein in E. coli in this transformant. It has been confirmed that the resulting &lgr; phage is capable of packaging &lgr; phage DNAs of 80% and 100% genome sizes. After further confirming that the nuclear localization signal exposed on the outside of the head of this phage, this phage has been microinjected into cells to analyze its nuclear localization activity. Thus, it has been clarified that this phage has a nuclear localization activity.