Newcastle Disease Virus-Vectored H7 and H5 Live Vaccines Protect Chickens from Challenge with H7N9 or H5N1 Avian Influenza Viruses

Abstract

e Sporadic human infections by a novel H7N9 virus occurred over a large geographic region in China. In this study, we show that Newcastle disease virus (NDV)-vectored H7 (NDV-H7) and NDV-H5 vaccines are able to induce antibodies with high hemagglutination inhibition (HI) titers and completely protect chickens from challenge with the novel H7N9 or highly pathogenic H5N1 viruses, respectively. Notably, a baculovirus-expressed H7 protein failed to protect chickens from H7N9 virus infection.A novel avian H7N9 influenza virus which emerged in poultry in China around March 2013 has caused more than 300 human infections and more than 100 deaths (1). More than 160 of these cases were reported in the first month of 2014. Because of the lack of an existing immunity against H7 subtype influenza viruses in the human population and domestic poultry and because of the absence of an available vaccine, there is a great concern that H7N9 virus may emerge as a potential pandemic virus for humans. In addition, the possible evolution of this low-pathogenicity H7N9 virus into a highly pathogenic virus for chickens is of concern (1, 3, 4). Sporadic human infections occurred over a large geographic region in China, suggesting a possible wide spread of H7N9 virus in poultry and at live poultry markets (5, 6). To date, no licensed commercial vaccine is available for the novel H7N9 virus in both avian species and humans. Vaccination could be a critical tool to prevent infection of domestic poultry and to prepare for a potential pandemic in humans.In this study, two H7 and two H5 vaccine candidates were investigated in chickens. The Newcastle disease virus (NDV)-vectored H7 (NDV-H7) vaccine was generated using reverse genetics to insert the ectodomain gene of the H7 hemagglutinin (HA) from Anhui/1/2013 H7N9 influenza virus between the P and M genes of an NDV vaccine strain (Lasota). To be recognized as an additional viral gene, the inserted sequence contained NDV's gene end (GE), intergenic (IS), and gene start (GS) sequences, as well as a Kozak sequence for efficient translation, preceding the H7 initiation codon (Fig. 1A). To improve the incorporation of the hemagglutinin ectodomain protein in the NDV, the transmembrane and cytoplasmic tail of the NDV F protein were fused to the C terminus of the ectodomain of the H7 protein (Fig. 1A). The ectodomain (amino acids 1 to 515) of the hemagglutinin protein of the novel H7N9 virus (A/Anhui/1/13) was expressed in a baculovirus system featuring a C-terminal trimerization domain as described before (7) and also evaluated in chickens. Additionally, NDV-H5 of a highly pathogenic avian influenza (HPAI) H5N1 virus (A/ chicken/Bali/U8661/2009, clade 2.1.3.2) and baculovirus-expressed recombinant H5 protein (from A/Vietnam/1203/04, clade 1) were tested in this study as well. The NDV-H5 and H5 subunit vaccine candidates were generated using the same strategy as that for the H7 vaccines (Fig. 1A). The H5 ectodomain sequence inserted in the NDV vector was modified to replace the multiple basic cleavage s...

Recombinant Newcastle disease virus expressing H9 HA protects chickens against heterologous avian influenza H9N2 virus challenge

“…Based on our results on the specific HI titers against NDV, an anamnestic booster response was found in chickens which had HI titers against NDV after the first vaccination via either the IM or ON administration route; this is consistent with our previous finding [49] and suggests that both the NDV-H9Con and NDV-H9Chi vaccines could work in chickens containing passively or actively acquired HI titers against NDV. However, the possible to use of these vaccines in ovo or in hatchlings with or without maternal antibodies needs to be investigated.…”

“…Another disadvantage of current widely used inactivated vaccines is that these kind of vaccines are not able to differentiate infected from vaccinated animals (DIVA), resulting in the difficulty of tracking animals infected with a circulating virus when conventional inactivated whole-virus vaccines are used [10, 46]. In this study we generated two NDV-based H9 vaccine candidates (NDV-H9Con and NDV-H9Chi) that have DIVA capability since the recombinant NDV viruses do not express the influenza NP that is normally used for the diagnostic purpose as described previously [30, 47–49]. Furthermore, both vaccines are highly immunogenic in chickens and provide protection against challenge with a heterologous H9N2 virus.…”

Live poultry vaccines against highly pathogenic avian influenza viruses

“…Immunization of chickens with NDV-vectored H5N1 vaccine provided a high level of protection against the clinical disease and mortality after lethal challenge with HPAIV of H5N1 subtype [24]. The NDV-vectored H7 and H5 vaccines were able to induce high antibody titers and completely protect chickens from challenge with the novel H7N9 and highly pathogenic H5N1 viruses [25]. The chimeric NDV vectored vaccine expressing the HA of A/Vietnam/1203/2004 (H5N1) was safe for 1-day-old chickens and provided a partial protection against challenge with A/Vietnam/1203/2004 HPAIV indicating the possibility of the early protection of chickens [26].…”

Characterizations of H4 avian influenza viruses isolated from ducks in live poultry markets and farm in Shanghai

“…For histopathologic examination and immunohistochemistry (IHC), lung samples were fixed in 10% buffered formalin, processed, and stained with hematoxylin and eosin (H&E). An anti-influenza A antibody against the nucleoprotein (Genscript, USA) was used for IHC staining as described previously23.…”