The impact of conservative and hypervariable immunodominant epitopes in internal proteins of the influenza A virus on cytotoxic T-cell immune responses

The cytotoxic T-cell immune response plays an important role in the prevention of influenza infection and reducing of the illness severity. The knowledge about mechanisms of the virus-specific CD8+ T-cell induction in humans is necessary for better understanding of influenza epidemiology and vaccine development. Due to application of new immunological and genetic methods in last years, considerable amount of.data became available in the literature about CD8+ T-cell immune responses to different influenza A viruses. This review summarizes these data. The main attention is paid to (i) heterosubtypic CTL responses to conservative immunodominant sites; (ii) mechanisms of viral escape from the virus-specific CTLs by means of evolutional escape-mutations; (iii) influence of the HLA haplotype on CD8+ T-cell immune responses. The importance of these data for immunology and vaccinology is discussed.