Understanding the “immunodominance” of Ab responses to Influenza A glycoproteins, HA and NA

Influenza A virus imposes a significant socio-economic burden on humanity.  Vaccination is effective in only 60% of individuals, even under optimal circumstances.  The difficulty stems from the remarkable ability of influenza A virus to evade existing immunity.  IAV’s error prone polymerase enables the rapid antigenic evolution of the two virion surface glycoproteins, neuraminidase (NA) and hemagglutinin (HA).  Since the most potent antibodies (Abs) at neutralizing viral infectivity are directed the HA and NA globular domains, amino acid substitutions in these regions enable IAV to evade Ab-based immunity.  The project focuses on understanding the “immunodominance” of Ab responses to HA and NA in humans.  Immunodominance describes the strong tendency of the immune response to respond to complex antigens in a hierarchical manner, with higher ranking, “immunodominant” antigens potentially suppressing (“immunodominating”) responses to “subdominant” antigens.  By focusing responses on single antigenic sites, it is likely responsible for enabling influenza A virus to evade immunity by allowing the virus to sequentially alter its antigenicity.