Spontaneous mutation at position 114 in H-2K(d) affects cytotoxic T cell responses to influenza virus infection

Vaccinia virus (VV)-encoded MHC class I K-d molecules which differ by a sin gle amino acid change from glutamine (K-dw, Wild type) to histidine (K-dm, mutant) at position 114 located in the floor of the peptide binding groove were compared in terms of peptide binding and cytotoxic T Ire) cell recogni tion. Most anti-viral Tc cells were not affected or only marginally affecte d. However, the K-dm molecule did not detectably present the immunodominant peptide (NPP147-155) Of influenza virus nucleoprotein (NP), encoded by the full-length NP gene either in influenza A virus or recombinant VV. This de fect could be overcome by using exogenous synthetic NPP147-155 Or translati on from a minigene encoding NPP147-155 in VV. K-dw presented NPP147-155 enc oded by the full-length NP gene, but K-dw-NPP147-155 complexes were at leas t 100-fold less abundant than after translation from a minigene.