In this study, we
asked three questions: (1) Can prior infection with an H1N1 swine
influenza virus (SIV) partially protect pigs from challenge with an
H5N1 LPAIV? (2) Can H1N1 infection-immunity also protect pigs
from challenge with an H5 AIV with a disparate NA, notably H5N2?
(3) Is protective immunity associated with cross-reactive antibody
to the N1 and/or cross-reactive cell-mediated immunity