title: Vaccination with formalin-inactivated influenza vaccine protects mice against lethal influenza Streptococcus pyogenes superinfection.
abstract: Intranasal infection with non-lethal influenza A virus (IAV) followed by infection with group A streptococci (GAS) induces invasive, lethal GAS infections, including necrotizing fasciitis, in mice. We demonstrate that subcutaneous immunization of formalin-inactivated IAV vaccine or intranasal immunization of IAV vaccine and cholera toxin protected more than 75% of mice from death by lethal IAV-GAS superinfection. The increased survival rate correlates with increase in IAV neutralizing activity and the levels of serum anti-IAV IgG. Moreover, elimination of IAV from the lungs of vaccinated mice led to depletion of GAS associated with alveolar epithelial cells. These findings suggest that formalin-inactivated IAV vaccine may be useful for prevention of secondary bacterial infections following prior IAV exposure.
authors.affiliation: Department of Oral and Molecular Microbiology, Osaka University Graduate School of Dentistry, 1-8 Yamada-oka Suita, 565-0871, Japan.
authors.forename: Shigefumi
authors.initials: S
authors.lastname: Okamoto
authors.forename: Shigetada
authors.initials: S
authors.lastname: Kawabata
authors.forename: Hideaki
authors.initials: H
authors.lastname: Fujitaka
authors.forename: Takashi
authors.initials: T
authors.lastname: Uehira
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Okuno
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Hamada
mesh_terms: D000281:Administration, Intranasal; D000818:Animals; D015169:Colony Count, Microbial; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005557:Formaldehyde; D007252:Influenza Vaccines / Q000276:immunology*; D007279:Injections, Subcutaneous; D051379:Mice; D008807:Mice, Inbred BALB C; D009976:Orthomyxoviridae Infections / Q000150:complications* / Q000401:mortality; D010587:Phagocytosis; D013290:Streptococcal Infections / Q000209:etiology* / Q000382:microbiology / Q000517:prevention & control*; D013297:Streptococcus pyogenes / Q000276:immunology*; D015163:Superinfection / Q000209:etiology* / Q000382:microbiology / Q000517:prevention & control*; D016019:Survival Analysis; D014613:Vaccines, Attenuated / Q000276:immunology
chemical_list: D007252:Influenza Vaccines; D014613:Vaccines, Attenuated; D005557:Formaldehyde