Differences in influenza virus receptors in chickens and ducks: Implications for interspecies transmission

Abstract

Avian influenza viruses are considered to be key contributors to the emergence of human influenza pandemics. A major determinant of infection is the presence of virus receptors on susceptible cells to which the viral haemagglutinin is able to bind. Avian viruses preferentially bind to sialic acid α2,3-galactose (SAα2,3-Gal) linked receptors, whereas human strains bind to sialic acid α2,6-galactose (SAα2,6-Gal) linked receptors. While ducks are the major reservoir for influenza viruses, they are typically resistant to the effects of viral infection, in contrast to the frequently severe disease observed in chickens. In order to understand whether differences in receptors might contribute to this observation, we studied the distribution of influenza receptors in organs of ducks and chickens using lectin histochemistry with linkage specific lectins and receptor binding assays with swine and avian influenza viruses. Although the intestinal epithelial cells of both species expressed only SAα2,3-Gal receptors, we found widespread presence of both SAα2,6-Gal and SAα2,3-Gal receptors in many organs of both chickens and ducks. Co-expression of both receptors may allow infection of cells with both avian and human viruses and so present a route to genetic reassortment. There was a marked difference in the primary receptor type in the trachea of chickens and ducks. In chicken trachea, SAα2,6-Gal was the dominant receptor type whereas in ducks SAα2,3-Gal receptors were most abundant. This suggests that chickens could be more important as an intermediate host for the generation of influenza viruses with increased ability to bind to SAα2,6-Gal receptors and thus greater potential for infection of humans. Chicken tracheal and intestinal epithelial cells also expressed a broader range of SAα2,3-Gal receptors (both β(1-4)GlcNAc and β(1-3)GalNAc subtypes) in contrast to ducks, which suggests that they may be able to support infection with a broader range of avian influenza viruses.

Structural basis for preferential avian receptor binding by the human-infecting H10N8 avian influenza virus

“…To examine the host tissue tropism of JD-H10N8 HA, we used soluble recombinant HA protein to stain paraffinized human trachea and duck intestinal tract sections. It is known that through lectin staining, the apical surface of the human trachea predominantly displays diverse glycan receptors terminated by a2,6 sialic acid linkages (human receptors) 18 , whereas the apical surface of the duck intestinal tract is full of diverse glycan receptors terminated by a2,3 sialic acid linkages (avian receptors) 19 . Consistent with the SPR experiments, JD-H10N8 HA did not stain the human trachea but stained the duck small intestine well (Fig.…”

Evidence of H1 and H3 Influenza Virus Infection in Captive Birds in Tehran from November 2008 to February 2009

“…On the other hand, previous studies indicate that quails play a significant role in the interspecies transmission of influenza virus from ducks to chickens (21). Domestic poultry such as quail and chicken possess α2, 3 and α2, 6 sialic acid receptors that may help passage of avian influenza viruses from bird species (such as ducks with only α2, 3 sialic acid receptor) to human with predominant α2, 6 sialic acid receptors (22,23). As sample collection of this study was undertaken in an environment that no pigs were kept, chicken and quail may have a key role in the transmission of influenza virus from birds to human and vice versa.…”

Induction of respiratory immune responses in the chicken; implications for development of mucosal avian influenza virus vaccines

“…Human influenza viruses prefer SA-2,6Gal-linkages, whereas avian viruses prefer SA-2,3Gal (Baigent and McCauley 2003). Both SA-2,3Gal-and SA-2,6Gal-linked receptors are widely expressed within different tissues, including the RT of poultry (Kuchipudi et al 2009;Pillai and Lee 2010;Yu et al 2011). This suggests that poultry can be infected with a wide range of influenza viruses and also probably act as a 'mixing vessel'.…”