An example of most frequently recognized conserved epitopes of influenza antigens in humans represents M1 58-66 CTL epitop, which is restricted by the high prevalence allele HLA-A*0201 and could be a promising vaccine candidate [120] . Computer programs available today can predict binding epitopes of a given protein for the most common HLA allele [121, 122] . In silico analysis supports the proposition that the T-cell response to cross-reactive T-cell epitopes induced by vaccination or seasonal viral exposition may have the capacity to attenuate the course of influenza infection in the absence of cross-reactive antibody response [123, 124] . The ability to predict the CTL epitope immunogenicity and recognition patterns of variant epitopes enhances the probability of the optimal selection of potential targets of immune response and can be utilized for vaccine design [93, 113, 125] . In spite of the differences in various classification schemes, the concept of HLA supertypes has been effectively used to characterize and identify promiscuously recognized T-cell epitopes from a variety of different disease targets, as are those of hepatitis C virus [126, 127] , SARS [128] or HIV [129, 130] but also influenza virus [131] .