Since a large peptide pool has been identified for these non-classical MHC-Ib molecules and since CD8+ T cells specific for Qa-1 and HLA-E exist [35], subtle structural differences in the peptide binding groove of these antigen-presenting molecules could potentially translate into appreciable differences in the selectivity or magnitude of the subsequent T cell response to Qa-1 or HLA-E binding peptides, especially during the cause of altered peptide presentation, such as during tumorigenesis or viral infection. The gene discussed is HLA-E; the disease is viral infectious disease.