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Dynamics of Dengue Virus (DENV)-Specific B Cells in the Response to DENV Serotype 1 Infections, Using Flow Cytometry With Labeled Virions.

BACKGROUND
The development of reagents to identify and characterize antigen-specific B cells has been challenging.


METHODS
We recently developed Alexa Fluor-labeled dengue viruses (AF DENVs) to characterize antigen-specific B cells in the peripheral blood of DENV-immune individuals.


RESULTS
In this study, we used AF DENV serotype 1 (AF DENV-1) together with AF DENV-2 on peripheral blood mononuclear cells (PBMCs) from children in Thailand with acute primary or secondary DENV-1 infections to analyze the phenotypes of antigen-specific B cells that reflected their exposure or clinical diagnosis. DENV serotype-specific and cross-reactive B cells were identified in PBMCs from all subjects. Frequencies of AF DENV(+) class-switched memory B cells (IgD(-)CD27(+) CD19(+) cells) reached up to 8% during acute infection and early convalescence. AF DENV-labeled B cells expressed high levels of CD27 and CD38 during acute infection, characteristic of plasmablasts, and transitioned into memory B cells (CD38(-)CD27(+)) at the early convalescent time point. There was higher activation of memory B cells early during acute secondary infection, suggesting reactivation from a previous DENV infection.


CONCLUSIONS
AF DENVs reveal changes in the phenotype of DENV serotype-specific and cross-reactive B cells during and after natural DENV infection and could be useful in analysis of the response to DENV vaccination.