Download Swine influenza (SwIV) is considered a zoonosis and the fact that

Swine influenza (SwIV) is considered a zoonosis and the fact that swine may act as an
intermediate reservoir for avian influenza virus, potentially infectious for humans, highlights
its relevance and the need to understand the interaction of different influenza viruses with the
porcine immune system. Dendritic cells (DC) link innate and adaptive immune system,
expressing specialized pattern-recognition receptors (PRRs) which recognise particular
pathogen-associateti molecular patterns (PAMPs). Furthermore, there is growing evidence
that the so-called"early" cytokines play an important role in influenza virus (IV) infection.
Thus, porcine DCs were exposed to different circulating IV in vitro showing a differential
wave of cytokines released upon encountering different IV strains. This prompted us te
investigate whether swine-adapted or non-adapted IV strains might give rise to peculiar
innate immune responses that could be correlated with pathological lesions in pigs. In fact,
each virus strain could be associated to cytokine gene and protein markers of infection.
These markers were observed well beyond the period of virus replication, which suggests a
prolonged homeostatic imbalance of the innate immune system following IV infection.
Interestingly, our data indicated that viruses from birds and seals have the potential to cross
the species barrier and establish successful infections in pigs. Interestingly, we could not
detect antibodies against HA after infection with viruses from birds and seals, not only in pigs
but also in infected mice. Therefore, increasing surveillance efforts must be directed to
identifying novel viruses with the capability to cross the species barrier, as well as new
diagnostic tools to detect these viruses in new hosts