It is conceivable to indicate that our New Linjudge Flu A/H5 could detect these occasionally emerged H5 viruses since the new kit efficiently detected their H5 LPAI prototype strains

It is conceivable to indicate that our New Linjudge Flu A/H5 could detect these occasionally emerged H5 viruses since the new kit efficiently detected their H5 LPAI prototype strains. persistently caused outbreaks in domestic poultry and wild birds worldwide and sporadically infected humans. Rapid and accurate diagnosis is one of the key strategies for the control of H5 HPAIVs. However, the sensitivity of the diagnosis of H5 HPAIVs has gradually reduced due to extensive antigenic variation during their evolution. Particularly, the previously developed immunochromatographic diagnosis kit for H5 viruses, Linjudge Flu A/H5, exhibits reduced detection of H5 HPAIVs isolated in recent years. In the present study, we established a new advanced H5 rapid immunochromatographic detection kit (New Linjudge Flu A/H5) by a combination of two anti-H5 hemagglutinin monoclonal antibodies, A64/1 Loxoprofen previously applied in the Linjudge Flu A/H5 and A32/2, a novel monoclonal antibody generated from a clade 2.3.4.4 H5 HPAIV. The new kit broadly detected all classical and recent H5 influenza viruses and showed a higher specificity and sensitivity than the original Linjudge Flu A/H5 with recently circulating H5 HPAIVs. Furthermore, the applicability of the New Linjudge Flu A/H5 was exhibited by detecting antigens from Loxoprofen the swabs and tissue homogenates of naturally infected birds and experimentally infected chickens with H5N6 HPAIVs belonging to the genetic clade 2.3.4.4. Our study, therefore, can provide an effective point-of-care rapid antigen detection kit for the surveillance of H5 avian influenza viruses and as a prompt countermeasure against the current widespread of the clade 2.3.4.4 H5 HPAIVs in domestic and wild birds. Introduction Influenza A virus (IAV) has been classified into different subtypes according to their surface glycoproteins, hemagglutinin (HA) and neuraminidase (NA), in which 16 HA (H1CH16) and 9 NA (N1CN9) subtypes were recognized [1]. Among IAV, an H5 subtype virus has become a NOS2A major global concern for the poultry industry since its first emergence in Guangdong, China in 1996, causing highly pathogenic avian influenza (HPAI) with at Loxoprofen least 75% fatality in infected birds [2,3]. After its reemergence in 2003, the virus has consequently caused thousands of outbreaks in poultry and spread rapidly across the world via migratory wild birds [4]. In addition, the zoonotic potential of the H5 HPAIV has been recognized since the first human case of an H5 HPAIV contamination in Hong Kong in 1997 [5]. To date, a total of 856 human infections with H5 HPAIVs were reported [6]. For controls of H5 HPAI in birds and H5 virus infection in humans, a simple, rapid, and accurate diagnostic tool is essential [7,8]. The typical diagnoses of IAV comprise serology or genetic identification; however, these methods are time-consuming and require appropriate facilities and biosafety [9]. In recent years, the simple and rapid immunochromatography (IC) technique, mainly based on antigen detection by monoclonal antibodies (MAbs), has been in focus because of its useful clinical diagnosis in humans and surveillance of contamination in the field in birds [9]. Several IC kits for detecting IAV and their specific subtypes are widely used for these purposes [10C17]. Efficacy of IC diagnosis for IAV to detect internal nucleoproteins (NP), a highly conserved protein of IAV and large-quantity expression in cells [18], is stable. Meanwhile, detection of HA determining specific subtypes of influenza viruses remains relatively less sensitive due to lower expression in cells and large variation of the surface protein [9]. In addition, circulation of H5 HPAIVs in domestic poultry and wild birds has led to extensive antigenic diversification, so-called antigenic drift [19]. This property of the virus has caused specific and sensitive diminution of MAb reactivity against varied antigens and consequently reduced efficacy of rapid diagnosis [20,21]. A previously developed H5 IC kit manufactured by a single MAb recognizing A/duck/Pennsylvania/10218/1984 (H5N2), Linjudge Flu A/H5, reduced the sensitivity and specificity to detect recent H5 HPAIVs. Therefore the primary component of IC, MAbs specifically recognizing variable H5 HA antigens, should be formulated according to variation of viral antigenicity for more effective detection [9]. In the present study, we established an improved H5 IC rapid diagnosis kit (New Linjudge Flu A/H5) using two MAbs; A64/1, originally used in the Linjudge Flu A/H5 [10], in addition to a newly generated MAb A32/2 against a clade 2.3.4.4 H5 HPAIV. The New Linjudge Flu A/H5 showed higher specificity and sensitivity to a broad range of H5 HPAIVs isolated in recent years compared to the original Linjudge Flu A/H5 kit. In addition, its diagnostic efficacy was comparable with an influenza detection kit recognizing NP, ImunoAce Flu (NP). The diagnostic applicability of the New Linjudge Flu A/H5 was reinforced by.