Phage display of peptide/major histocompatibility class I complexes

Major histocompatibility complex class I (MHC-I) molecules sample peptides from the intracellular environment and present them to cytotoxic T cells (C TL). To establish a selection system, and, thereby, enable a library approa ch to identify the specificities involved (that of the MHC-I for peptides a nd subsequently that ct the T cell receptor for peptide-MHC-I complex), we have fused a single chain peptide-MHC-I complex to the phage minor coat pro tein, gpIII, and displayed it on filamentous phage. Expression of peptide-M HC-I complexes was shown with relevant conformation-specific monoclonal ant ibodies and, more importantly, with a unique "T cell receptor-like" (i.e. p eptide-specific, MHC-I-restricted) antibody. Thus, properly assembled and f olded peptide-MHC-I complexes can be displayed on filamentous phage. Despit e the successful display, interaction with T cells could not be demonstrate d.