Journal or Book Title
Live-attenuated influenza virus (LAIV) prime-boost vaccination previously conferred protection against heterologous H3N2 swine influenza challenge, including in piglets with maternally derived antibodies (MDA). Conversely, a whole-inactivated virus (WIV) vaccine was associated with enhanced disease. This study was aimed at identifying immune correlates of cross-protection. Piglets with and without MDA received intramuscular adjuvanted WIV or intranasal LAIV, and were challenged with heterologous H3N2. WIV induced cross-reactive IgG, inhibited by MDA, and a moderate T cell response. LAIV elicited mucosal antibodies and T cells cross-reactive to the heterologous challenge strain. The presence of MDA at LAIV vaccination blocked lung and nasal antibody production, but did not interfere with T cell priming. Even without mucosal antibodies, MDA-positive LAIV vaccinates were protected, indicating a likely role for T cells. Based on the data, one LAIV dose can induce cell-mediated immunity against antigenically divergent H3N2 influenza virus despite passive antibody interference with humoral immune responses.
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Sandbulte, Matthew Robert; Platt, Ratree; Roth, James A.; Henningson, Jamie N.; Gibson, Kathleen A.; Rajão, Daniela S.; Loving, Crystal Lynn; and Vincent, Amy L., "Divergent Immune Responses and Disease Outcomes in Piglets Immunized with Inactivated and Attenuated H3N2 Swine Influenza Vaccines in the Presence of Maternally-Derived Antibodies" (2014). Veterinary Microbiology and Preventive Medicine Publications. 76.