title: Live attenuated influenza vaccine (LAIV) impacts innate and adaptive immune responses.
abstract: Influenza A infection induces a massive inflammatory response in the lungs that leads to significant illness and increases the susceptibility to secondary bacterial pneumonia. The most efficient way to prevent influenza infection is through vaccination. While inactivated vaccines induce protective levels of serum antibodies to influenza hemaglutinin (HA) and neuraminidase (NA) surface proteins, these are strain specific and offer little protection against heterosubtypic influenza viruses. In contrast, live attenuated influenza vaccines (LAIVs) induce a T cell response in addition to antibody responses against HA and NA surface proteins. Importantly, LAIV vaccination induces a response in a mouse model that protects against illness due to heterosubtypic influenza strains. While it is not completely clear what is the mechanism of action of LAIV heterosubtypic protection in humans, it has been shown that LAIV induces heterosubtypic protection in mice that is dependent upon a Type 1 immune response and requires CD8 T cells. In this study, we show that LAIV-induced immunity leads to significantly reduced viral titers and inflammatory responses in the lungs of mice following heterosubtypic infection. Not only are viral titers reduced in LAIV vaccinated mice, the amounts of inflammatory cytokines and chemokines in lung tissue are significantly lower. Additionally, we show that LAIV vaccination of healthy adults also induces a robust Type 1 memory response including the production of chemokines and cytokines involved in T cell activation and recruitment. Thus, our results indicate that LAIV vaccination functions by inducing immune memory which can act to modulate the immune response to subsequent heterosubtypic challenge by influencing both innate and adaptive responses.
authors.affiliation: Trudeau Institute, Saranac Lake, NY 12983, USA.
authors.forename: Paula A
authors.initials: PA
authors.lastname: Lanthier
authors.forename: Gail E
authors.initials: GE
authors.lastname: Huston
authors.forename: Amy
authors.initials: A
authors.lastname: Moquin
authors.forename: Sheri M
authors.initials: SM
authors.lastname: Eaton
authors.forename: Frank M
authors.initials: FM
authors.lastname: Szaba
authors.forename: Lawrence W
authors.initials: LW
authors.lastname: Kummer
authors.forename: Micheal P
authors.initials: MP
authors.lastname: Tighe
authors.forename: Jacob E
authors.initials: JE
authors.lastname: Kohlmeier
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Blair
authors.forename: Michael
authors.initials: M
authors.lastname: Broderick
authors.forename: Stephen T
authors.initials: ST
authors.lastname: Smiley
authors.forename: Laura
authors.initials: L
authors.lastname: Haynes
mesh_terms: D000328:Adult; D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry / Q000166:cytology / Q000276:immunology; D056738:Cross Protection; D016207:Cytokines / Q000032:analysis / Q000276:immunology; D006805:Human Experimentation; D006801:Humans; D007249:Inflammation / Q000276:immunology / Q000473:pathology; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000276:immunology*; D008168:Lung / Q000276:immunology / Q000473:pathology / Q000821:virology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000276:immunology; D019562:Viral Load
chemical_list: D016207:Cytokines; D007252:Influenza Vaccines; D014613:Vaccines, Attenuated