Limited cross-reactivity of mouse monoclonal antibodies against Dengue virus capsid protein among four serotypes

Abstract

BackgroundDengue illness is one of the important mosquito-borne viral diseases in tropical and subtropical regions. Four serotypes of dengue virus (DENV-1, DENV-2, DENV-3, and DENV-4) are classified in the Flavivirus genus of the family Flaviviridae. We prepared monoclonal antibodies against DENV capsid protein from mice immunized with DENV-2 and determined the cross-reactivity with each serotype of DENV and Japanese encephalitis virus.Methods and resultsTo clarify the relationship between the cross-reactivity of monoclonal antibodies and the diversity of these viruses, we examined the situations of flaviviruses by analyses of phylogenetic trees. Among a total of 60 prepared monoclonal antibodies specific for DENV, five monoclonal antibodies stained the nuclei of infected cells and were found to be specific to the capsid protein. Three were specific to DENV-2, while the other two were cross-reactive with DENV-2 and DENV-4. No monoclonal antibodies were cross-reactive with all four serotypes. Phylogenetic analysis of DENV amino acid sequences of the capsid protein revealed that DENV-2 and DENV-4 were clustered in the same branch, while DENV-1 and DENV-3 were clustered in the other branch. However, these classifications of the capsid protein were different from those of the envelope and nonstructural 1 proteins. Phylogenetic distances between the four serotypes of DENV were as different as those of other flaviviruses, such as Japanese encephalitis virus and West Nile virus. Large variations in the DENV serotypes were comparable with the differences between species of flavivirus. Furthermore, the diversity of flavivirus capsid protein was much greater than that of envelope and nonstructural 1 proteins.ConclusionIn this study, we produced specific monoclonal antibodies that can be used to detect DENV-2 capsid protein, but not a cross-reactive one with all serotypes of DENV capsid protein. The high diversity of the DENV capsid protein sequence by phylogenetic analysis supported the low cross-reactivity of monoclonal antibodies against DENV capsid protein.

Understanding Dengue Virus Capsid Protein Interaction with Key Biological Targets

“…DENV belongs to the Flavivirus genus and Flaviviridae family 21 , a taxon that includes other major human pathogens, such as the yellow fever virus, West Nile virus and hepatitis C virus, among others 21 22 . These viruses share common life cycle features and similar virion structure 21 , with homologous proteins presenting highly conserved regions 21 23 24 . The viral particle is relatively simple: a lipid bilayer, where the envelope and membrane proteins are located, surrounds a nucleocapsid where a positive sense single-stranded genomic RNA forms a complex with multiple copies of the capsid (C) protein 25 .…”