Hongxia Shao

Duck adenovirus 3 (DAdV-3), a newly emerged duck adenovirus, has resulted in significant economic losses to the duck industry across China since 2014. However, little is known about the B cell epitopes in major antigen of DAdV-3 and the serological approach for detection of DAdV-3 is not available. In this study, four monoclonal antibodies (mAbs) specific to Fiber-2 protein of DAdV-3 were first generated and designated as 2G10, 3D9, 5E6, and 6B12. Indirect immunofluorescence assay (IFA) showed that all of the mAbs reacted with the Fiber-2. Moreover, mAbs 2G10, 5E6, and 6B12 demonstrated good activity with Fiber-2 in Western blot. Notably, the Fiber-2 could be immunoprecipitated efficiently by mAb 3D9. Epitope mapping revealed that mAbs 2G10, 3D9, 5E6, and 6B12 recognized 397-429aa, 463-481aa, 67-99aa, and 1-66aa of Fiber-2, respectively. Besides, a novel sandwich ELISA for efficient detection of DAdV-3 was developed based on mAb 3D9 and horseradish peroxidase (HRP) conjugated mAb 3D9. The sandwich ELISA only reacted with DAdV-3 but not with other duck-associated viruses. The limit of detection of the ELISA was 6.25 × 10³ TCID₅₀/mL. Overall, the mAbs generated laid the foundation for elucidating the critical role of Fiber-2 in mediating infection and pathogenesis, and the sandwich ELISA approach established here provided efficient and rapid serological diagnostic tool for DAdV-3.

The outbreak of goose gout disease caused by novel goose astrovirus type 1 (GAstV-1) has resulted in huge economic losses to the goose industry in China si

In China, although the ALV eradication program and the MD vaccination strategy greatly reduce the disease burdens caused by the infection of ALV and MDV, the frequent emergence of novel ALV-K or vvMDV in the vaccinated chicken flock challenges the current control strategies for both diseases. In Guangdong Province, an indigenous chicken flock was infected with neoplastic disease. Hematoxylin–eosin staining of the tissues showed the typical characteristics of MDV and classical ALV infection. The PCR and sequencing data demonstrated that the identified MDV was clustered into a very virulent MDV strain endemic in domestic chickens in China. Moreover, subgroups ALV-A and ALV-K were efficiently recovered from two samples. The full genome sequence revealed that the ALV-K isolate was phylogenetically close to the ALV TW3593 isolate from Taiwan Province. A co-infection of vvMDV with multiple ALV subgroups emerged in a chicken flock with neoplastic disease in Guangdong Province. The co-infection with different subgroups of ALV with vvMDV in one chicken flock poses the risk for the emergence of novel ALVs and heavily burdens the control strategy for MDV.

Recently, serotype 4 fowl adenovirus (FAdV-4) has spread widely and caused huge economic loss to poultry industry. However, little is known about the molecular pathogenesis of FAdV-4. Fiber protein is thought to be vital for its infection and pathogenesis. Two novel monoclonal antibodies (mAbs) targeting the fiber-1 protein of FAdV-4 were generated, designated as mAb 3B5 and 6H9 respectively. Indirect immunofluorescence assay (IFA) showed that both mAbs only reacted with the FAdV-4 and FAdV-10, not with other serotypes including FAdV-1, FAdV-5, FAdV-6, FAdV-7, FAdV-8 and FAdV-9 tested. Although both mAbs did not recognize the linear epitopes, they could efficiently immunoprecipitate the fiber-1 protein in LMH cells either infected with FAdV-4 or transfected with pcDNA3.1-Fiber-1. Moreover, mAb 3B5 as a capture antibody and HRP-conjugated mAb 6H9 as a detection antibody, a novel sandwich ELISA for efficient detection of FAdV-4 was generated. The limit of detection of the ELISA could reach to 1000 TCID50/ml of FAdV-4 and the ELISA could be efficiently applied to detect FAdV-4 in the clinical samples. The two mAbs specific targeting fiber-1 generated here would pave the way for further studying on the role of fiber-1 in the infection and pathogenesis of FAdV-4, and the established mAb based sandwich ELISA would provide an efficient diagnostics tool for detection of FAdV-4/10.