title: Cellular and humoral cross-immunity against two H3N2v influenza strains in presumably unexposed healthy and HIV-infected subjects.
abstract: Human cases of infection due to a novel swine-origin variant of influenza A virus subtype H3N2 (H3N2v) have recently been identified in the United States. Pre-existing humoral and cellular immunity has been recognized as one of the key factors in limiting the infection burden of an emerging influenza virus strain, contributing to restrict its circulation and to mitigate clinical presentation. Aim of this study was to assess humoral and cell-mediated cross immune responses to H3N2v in immuno-competent (healthy donors, n = 45) and immuno-compromised hosts (HIV-infected subjects, n = 46) never exposed to H3N2v influenza strain. Humoral response against i) H3N2v (A/H3N2/Ind/08/11), ii) animal vaccine H3N2 strain (A/H3N2/Min/11/10), and iii) pandemic H1N1 virus (A/H1N1/Cal/07/09) was analysed by hemagglutination inhibition assay; cell-mediated response against the same influenza strains was analysed by ELISpot assay. A large proportion of healthy and HIV subjects displayed cross-reacting humoral and cellular immune responses against two H3N2v strains, suggesting the presence of B- and T-cell clones able to recognize epitopes from emerging viral strains in both groups. Specifically, humoral response was lower in HIV subjects than in HD, and a specific age-related pattern of antibody response against different influenza strains was observed both in HD and in HIV. Cellular immune response was similar between HD and HIV groups and no relationship with age was reported. Finally, no correlation between humoral and cellular immune response was observed. Overall, a high prevalence of HD and HIV patients showing cross reactive immunity against two H3N2v strains was observed, with a slightly lower proportion in HIV persons. Other studies focused on HIV subjects at different stages of diseases are needed in order to define how cross immunity can be affected by advanced immunosuppression.
authors.affiliation: Laboratory of Virology, National Institute for Infectious Diseases "Lazzaro Spallanzani" I.R.C.C.S., Rome, Italy; Laboratory of Cellular Immunology, National Institute for Infectious Diseases "Lazzaro Spallanzani" I.R.C.C.S., Rome, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Agrati
authors.affiliation: Laboratory of Virology, National Institute for Infectious Diseases "Lazzaro Spallanzani" I.R.C.C.S., Rome, Italy.
authors.forename: Concetta
authors.initials: C
authors.lastname: Castilletti
authors.affiliation: Laboratory of Cellular Immunology, National Institute for Infectious Diseases "Lazzaro Spallanzani" I.R.C.C.S., Rome, Italy.
authors.forename: Eleonora
authors.initials: E
authors.lastname: Cimini
authors.affiliation: Laboratory of Virology, National Institute for Infectious Diseases "Lazzaro Spallanzani" I.R.C.C.S., Rome, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Lapa
authors.affiliation: Laboratory of Virology, National Institute for Infectious Diseases "Lazzaro Spallanzani" I.R.C.C.S., Rome, Italy.
authors.forename: Serena
authors.initials: S
authors.lastname: Quartu
authors.affiliation: Laboratory of Virology, National Institute for Infectious Diseases "Lazzaro Spallanzani" I.R.C.C.S., Rome, Italy.
authors.forename: Claudia
authors.initials: C
authors.lastname: Caglioti
authors.affiliation: Epidemiology Department, National Institute for Infectious Diseases "Lazzaro Spallanzani" I.R.C.C.S., Rome, Italy.
authors.forename: Simone
authors.initials: S
authors.lastname: Lanini
authors.affiliation: Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro, Padova, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Cattoli
authors.affiliation: Laboratory of Cellular Immunology, National Institute for Infectious Diseases "Lazzaro Spallanzani" I.R.C.C.S., Rome, Italy.
authors.forename: Federico
authors.initials: F
authors.lastname: Martini
authors.affiliation: Epidemiology Department, National Institute for Infectious Diseases "Lazzaro Spallanzani" I.R.C.C.S., Rome, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Ippolito
authors.affiliation: Laboratory of Virology, National Institute for Infectious Diseases "Lazzaro Spallanzani" I.R.C.C.S., Rome, Italy.
authors.forename: Maria R
authors.initials: MR
authors.lastname: Capobianchi
mesh_terms: D000328:Adult; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D001402:B-Lymphocytes / Q000276:immunology / Q000821:virology; D056738:Cross Protection; D005260:Female; D015658:HIV Infections / Q000276:immunology* / Q000473:pathology / Q000821:virology; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D007111:Immunity, Cellular; D056724:Immunity, Humoral; D016867:Immunocompromised Host; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology*; D053122:Influenza A Virus, H3N2 Subtype / Q000276:immunology*; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000276:immunology; D007251:Influenza, Human / Q000276:immunology* / Q000473:pathology / Q000517:prevention & control / Q000821:virology; D008297:Male; D008875:Middle Aged; D013552:Swine; D013601:T-Lymphocytes / Q000276:immunology / Q000821:virology; D014611:Vaccination
chemical_list: D000914:Antibodies, Viral; D007252:Influenza Vaccines