Clade 2.3.4.4, H5 subtype highly pathogenic avian influenza viruses (HPAIVs) have caused devastating effects across wild and domestic bird populations. We investigated differences in the intensity and distribution of the hemagglutinin (HA) glycoprotein binding of a clade 2.3.4.4 H5 HPAIV compared to a H5 low pathogenic avian influenza virus (LPAIV). Recombinant HA from gene sequences from a HPAIV, A/Northern pintail/Washington/40964/2014(H5N2) and a LPAIV, A/mallard/MN/410/2000(H5N2) were generated and, via protein histochemistry, HA binding in respiratory, intestinal and cloacal bursal tissue was quantified as median area of binding (MAB). Poultry species, shorebirds, ducks and terrestrial birds were used. Differences in MAB were observed between the HPAIV and LPAIV H5 HAs. We demonstrate that clade 2.3.4.4 HPAIV H5 HA has a broader tropism across a variety of bird species compared to the LPAIV H5 HA. These findings support published results from experimental trials, and outcomes of natural disease outbreaks with these viruses. Graphical Abstract Avian influenza virus Hemagglutinin (HA) glycoprotein tissue binding is visible by dark brown staining using 3,3-diaminobenzimidine (DAB) HRP with protein histochemistry. Extensive, HA binding is observed in the ciliated epithelial cells of the trachea and the goblet cells of the ceca of both mallards and chickens.
【저자키워드】 hemagglutinin, tropism, Recombinant protein, poultry, H5N2, Highly pathogenic avian influenza virus, waterfowl, Low pathogenic avian influenza virus, terrestrial birds,