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Huang X, Huang J, Yin G, Cai Y, Chen M, Hu J, Feng X. Identification of NP Protein-Specific B-Cell Epitopes for H9N2 Subtype of Avian Influenza Virus. Viruses 2022; 14:v14061172. [PMID: 35746647 PMCID: PMC9228734 DOI: 10.3390/v14061172] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 05/25/2022] [Accepted: 05/26/2022] [Indexed: 02/01/2023] Open
Abstract
Avian Influenza (AI) caused by the H9N2 subtype of the avian influenza virus (AIV) poses a serious threat to both the poultry industry and to public health safety. NP is one of the major structural proteins in influenza viruses. B-cell determinants located on NP proteins have attracted increasing attention. In this study, based on the NP sequence of the H9N2 (A/chicken/Shandong/LY1/2017) strain, the truncated NP gene (71 AA–243 AA) was cloned and prokaryotically expressed in a pET-28a (+) vector. BALB/c mice were immunized with a purified recombinant of an NP protein to prepare a monoclonal antibody against NP proteins. The prokaryotic expression of four overlapping fragments, NP-N-96, NP-C-103, NP-C-54 and NP-C-49, were used to recognize an antigenic epitope of the NP protein. The results show that, after cell fusion, one hybridoma cell clone secreted the antibody specific to the NP protein, following screening with ELISA and indirect immunofluorescence, which is named the 4F5 monoclonal antibody (mAb). Western blotting on the overlapping fragments showed that the 230FQTAAQRA237 motif was identified as the minimal motif recognized by 4F5mAb, which was represented as the linear B-cell epitope of the NP protein. Homology analysis of this epitope shows that it was highly conserved in 18 AIVs analyzed in this study, and the epitope prediction results indicate that the epitope may be located on the surface of the NP protein. These results provide a strong experimental basis for studying the function of the NP protein of the H9N2 AIV and also strong technical support for the development of a universal assay based on an anti-NP monoclonal antibody.
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Affiliation(s)
- Xiangyu Huang
- Key Laboratory of Animal Microbiology of China’s Ministry of Agriculture, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; (X.H.); (J.H.); (G.Y.); (Y.C.); (M.C.); (J.H.)
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China
| | - Jingwen Huang
- Key Laboratory of Animal Microbiology of China’s Ministry of Agriculture, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; (X.H.); (J.H.); (G.Y.); (Y.C.); (M.C.); (J.H.)
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China
| | - Guihu Yin
- Key Laboratory of Animal Microbiology of China’s Ministry of Agriculture, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; (X.H.); (J.H.); (G.Y.); (Y.C.); (M.C.); (J.H.)
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China
| | - Yiqin Cai
- Key Laboratory of Animal Microbiology of China’s Ministry of Agriculture, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; (X.H.); (J.H.); (G.Y.); (Y.C.); (M.C.); (J.H.)
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China
| | - Mengli Chen
- Key Laboratory of Animal Microbiology of China’s Ministry of Agriculture, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; (X.H.); (J.H.); (G.Y.); (Y.C.); (M.C.); (J.H.)
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China
| | - Jianing Hu
- Key Laboratory of Animal Microbiology of China’s Ministry of Agriculture, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; (X.H.); (J.H.); (G.Y.); (Y.C.); (M.C.); (J.H.)
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China
| | - Xiuli Feng
- Key Laboratory of Animal Microbiology of China’s Ministry of Agriculture, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China; (X.H.); (J.H.); (G.Y.); (Y.C.); (M.C.); (J.H.)
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China
- Correspondence: ; Tel.: +86-25-8439-6028
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Sarfraz M, Nguyen TTT, Wheler C, Köster W, Gerdts V, Dar A. Characterization of Dosage Levels for In Ovo Administration of Innate Immune Stimulants for Prevention of Yolk Sac Infection in Chicks. Vet Sci 2022; 9:vetsci9050203. [PMID: 35622731 PMCID: PMC9142911 DOI: 10.3390/vetsci9050203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 04/16/2022] [Accepted: 04/21/2022] [Indexed: 02/04/2023] Open
Abstract
Innate immune stimulants, especially toll-like receptor (TLR) ligands and agonists, are the main players in the initiation of innate immunity and have been widely studied as alternatives to antibiotics to control infection. In the present study, we characterized the dosage levels of various innate immune stimulants, including unmethylated cytosine-phosphate-guanosine dinucleotide -containing oligodeoxynucleotides (CpG ODN), polyinosinic-polycytidylic acid (poly I:C), cyclic polyphosphazene 75B (CPZ75B), avian beta-defensin 2 (ABD2), and combinations of these reagents given in ovo. Data derived from a series of animal experiments demonstrated that the in ovo administration of 10–50 µg CpG ODN/embryo (on embryonic day 18) is an effective formulation for control of yolk sac infection (YSI) due to avian pathogenic Escherichia coli (E. coli) in young chicks. Amongst the different combinations of innate immune stimulants, the in ovo administration of CpG ODN 10 µg in combination with 15 µg of poly I:C was the most effective combination, offering 100% protection from YSI. It is expected that the introduction of these reagents to management practices at the hatchery level may serve as a potential replacement for antibiotics for the reduction of early chick mortality (ECM) due to YSI/colibacillosis.
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