Back to the future: Immunization with M-001 prior to trivalent influenza vaccine in 2011/12 enhanced protective immune responses against 2014/15 epidemic strain.

We previously reported a 2011/12 study in elderly showing that immunization with the universal influenza vaccine candidate, M-001, three weeks before administering trivalent influenza vaccine (TIV) enhanced seroconversion of Hemagglutination Inhibition (HAI) antibodies against known influenza vaccine strains circulating at that time. We now report that those subjects primed with M-001 prior to TIV in 2011 also showed, in their 2011 sera, significantly more HAI antibodies with improved seroprotection and seroconversion against strain A/Switzerland/9715293/2013(H3N2-like) that caused the 2014/15 influenza epidemic and that wasn't known to circulate in 2011/12. These data indicate that M-001 can provide broadened enhanced immunity extending even to influenza strains destined to circulate in future years. The fact that M-001 stimulates T cell activation and is devoid of HA hypervariable epitopes indicates that such broadened HAI responses effected by M-001 priming is due to extensive T cell priming.