Establishment and application of a gold nanoparticle-based immunochromatographic test strip for the detection of avian leukosis virus P27 antigen in egg white samples.

Avian leukemia is an infectious tumorous disease of chickens caused by subgroup A of the avian leukemia virus (ALV-A), which mainly causes long-term viremia, slow growth, immune suppression, decreased production performance, multi-tissue tumors, and even death. The infection rate of this disease is very high in chicken herds in China, causing huge economic losses to the poultry industry every year. We successfully expressed the specific antigen protein of ALV (P27) through recombinant protein technology and screened a pair of highly sensitive monoclonal antibodies (mAbs) through mouse immunity, cell fusion, and antibody pairing. Based on this pair of antibodies, we established a dual antibody sandwich ELISA and gold nanoparticle immunochromatographic strip (AuNP-ICS) detection method. In addition, the parameters of the dual antibody sandwich ELISA and AuNP-ICS were optimized under different reaction conditions, which resulted in the minimum detection limits of 0.2 ng mL-1 and 1.53 ng ml-1, respectively. Commonly available ELISA and AuNP-ICS products on the market were compared, and we found that our established immune rapid chromatography had higher sensitivity. This established AuNP-ICS had no cross-reactivity with Influenza A (H1N1), Influenza A (H9N2), respiratory syncytial virus (RSV), varicella-zoster virus (VZV), Listeria monocytogenes listeriolysin (LLO), and Staphylococcal enterotoxin SED or SEC. Finally, the established AuNP-ICS was used to analyze 35 egg samples, and the results showed 5 positive samples and 30 negative samples. The AuNP-ICS rapid detection method established by our group had good specificity, high sensitivity, and convenience, and could be applied to the clinical sample detection of ALV-A.

Factors influencing customers' dine out intention during COVID-19 reopening period: The moderating role of country-of-origin effect.

COVID-19 pandemic negatively affected the restaurant industry and reopening provides restaurants an opportunity to survive this crisis. This study examined the interplay of perceived importance of preventive measures, dining involvement, brand trust, and customers' intention to dine out at American Chinese restaurants during the reopening period. Additionally, the study investigated the moderating role of country-of-origin (COO) effect on these relationships. 296 U.S. restaurant customers recruited via a market research company completed the online survey. Structural equation modeling was used for data analyses. The results indicated that dining involvement had a direct positive effect on customers' intention to dine out. Moreover, both perceived importance of preventive measures and dining involvement could enhance customers' intention to dine out indirectly via brand trust. Positive COO effect moderated the relationship between perceived importance of preventive measures and brand trust. The study provided significant implications for restaurant operators in the U.S during the reopening period.