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Canine distemper (CD) is a highly contagious, systemic, viral disease of dogs seen worldwide. The nucleocapsid protein (NP) of canine distemper virus encloses virus assembly and has some regulatory functions in viral transcription and replication. Here, we describe a procedure to generate a monoclonal antibody (MAb) against CDV N protein and investigate its characteristics. Western blot analysis showed that the MAbs produced in this study were against CDV N specifically. Indirect immunofluorescence assay demonstrated that they could recognize native N protein in CDV-infected Vero cells. The MAbs reported here may provide valuable tools for the further exploration of biological properties and functions of N protein and may also be developed for potential clinical applications. [ABSTRACT FROM AUTHOR]

Highlights • Firstly, we recognize four epitopes of CDV phosphoprotein, 238SHGMGIVAGSTN249, 264GPSVSAENVRQ274, 390INPELRPIIGR400 and 252TQSALKSTG260. • Secondly, the linear B-cell epitope of the Pc11 MAb is relatively conserved among different CDV strains. • Thirdly, the E27-2 might be a common B-cell binding epitope of CDV antibodies and provide new diagnostic assays for CDV. • Finally, the Pc8 MAb can distinguish the infections with the currently circulating CDV from the vaccine strains of CDV. Abstract The highly contagious canine distemper virus (CDV) is a non-segmented single-stranded negative-sense RNA virus, which belongs to the Morbillivirus genus of the Paramyxoviridae family. The phosphoprotein (P) of CDV plays the important role in the virus replication and pathogenesis. In this study, we characterized four monoclonal antibodies (MAbs), designated as Pc7, Pc8, Pc11 and Pc25 MAbs against the P protein of CDV-PS strain. A series of overlapping P protein-derived peptides representing the CDV-PS phosphoprotein (aa232-507) were screened to identify linear peptide epitopes recognized by each MAb. Finally, four epitopes, 238SHGMGIVAGSTN249 (E2-9), 264GPSVSAENVRQ274 (E6-2), 390INPELRPIIGR400 (E27-2) and 252TQSALKSTG260 (E4-9), are minimal linear epitopes recognized by the Pc7, Pc8, Pc11 and Pc25 MAbs, respectively. Each identified B-cell epitope was able to be recognized by CDV positive dog serum. Alignment analysis of the amino acid sequences indicated that the linear B-cell epitope of the Pc11 MAb is relatively conserved among different CDV strains, but the linear B-cell epitopes recognized by Pc7, Pc8 and Pc25 MAbs are not conserved among CDV strains. Our results revealed that the E27-2 peptide might be a common B-cell binding epitope of CDV antibodies. These findings may provide a useful basis for the development of new diagnostic assays for CDV. [ABSTRACT FROM AUTHOR]

Aleutian mink disease virus (AMDV) is a parvovirus that causes an immune complex-mediated disease in minks. Capsid protein VP2 is a major structural viral protein and can be used to diagnose AMDV. In this study, a specific monoclonal antibody, 1M13, was produced against the AMDV VP2 protein (amino acids 291–502). A linear VP2-protein epitope was identified by subjecting a series of partially overlapping synthesized peptides to be enzyme-linked immunosorbent assay (ELISA) analysis. The results indicated that 386 HLQQNFSTRYIYD 398 was the minimal linear epitope that could be recognized by mAb 1M13. ELISA assays revealed that mink anti-AMDV sera could also recognize the minimal linear epitope. Sequence alignments demonstrated that the linear epitope is highly conserved among AMDV strains except 386 H and is less conserved among Raccoon dog amdovirus, Gray fox amdovirus, Red fox amdovirus, Bat parvovirus and Mink enteritis parvovirus. Taken together, the generation of this VP2-specific mAb with a defined linear peptide epitope may have potential applications in the development of suitable diagnostic techniques for AMDV. [ABSTRACT FROM AUTHOR]

Canine distemper virus (CDV) is a member of the genus Morbillivirus within the family Paramyxoviridae and has caused severe economic losses in China. Nucleocapsid protein (N) is the major structural viral protein and can be used to diagnose CDV and other morbilliviruses. In this study, a specific monoclonal antibody, 1N8, was produced against the CDV N protein (amino acids 277–471). A linear N protein epitope was identified by subjecting a series of partially overlapping synthesized peptides to enzyme-linked immunosorbent assay (ELISA) analysis. The results indicated that 350 LNFGRSYFDPA 360 was the minimal linear epitope that could be recognized by mAb 1N8. ELISA assays revealed that mouse anti-CDV sera could also recognize the minimal linear epitope. Alignment analysis of the amino acid sequences indicated that the epitope was highly conserved among CDV strains. Furthermore, the epitope was conserved among other morbilliviruses, which was confirmed with PRRV using western blotting. Taken together, the results of this study may have potential applications in the development of suitable diagnostic techniques for CDV or other morbilliviruses. [ABSTRACT FROM AUTHOR]