Plasmablasts Generated during Repeated Dengue Infection Are Virus Glycoprotein–Specific and Bind to Multiple Virus Serotypes

Abstract

Dengue virus immune protection is specific to the serotype encountered and is thought to persist throughout one’s lifetime. Many serotype cross-reactive memory B cells isolated from humans with previous dengue infection are specific for the nonstructural and the prM structural viral proteins, and they can enhance infection in vitro. However, plasmablasts circulating in enormous numbers during acute secondary infection have not been studied. In this study, we analyzed single plasmablasts from two patients by sorting the cells for Ig sequence analysis and for recombinant expression of Abs. In contrast to memory B cells, most plasmablast-derived Abs bound to the structural E protein of dengue, and protection experiments in mice revealed that virus serotypes encountered during past infections were neutralized more efficiently than were the serotypes of the current infection. Together with genetic analyses, we show evidence that plasmablasts in dengue patients are a polyclonal pool of activated E protein–specific memory B cells and that their specificity is not representative of the serum Abs secreted by long-lived plasma cells in the memory phase. These results contribute to the understanding of the phenomenon of original antigenic sin in dengue.

B Cell Responses during Secondary Dengue Virus Infection Are Dominated by Highly Cross-Reactive, Memory-Derived Plasmablasts

“…The surface glycoprotein E has been described as an important target in the human immune response to DENV infection (23,25,42,43). More recently, two groups derived MAbs from dengue patient ASCs and demonstrated that the E protein contains major epitopes for antibody binding and viral neutralization during ongoing infection (29,44). As expected, a majority of MAbs (31/53) in our panel bound to rE.…”

“…Previous studies have shown that the viral structural protein E is a major antigenic target for human humoral responses to DENV (17,23,25,29). We tested the MAb panel for reactivity to E by performing ELISAs with DENV1 to -4 recombinant envelope (rE) proteins.…”

“…We and other groups have shown that a rapid and massive expansion of plasmablasts occurs during the acute phase of human DENV infection (27)(28)(29). Plasmablasts can account for as many as 30% of all peripheral lymphocytes in patients a few days to a week post-fever onset (27).…”

Human antibody responses after dengue virus infection are highly cross-reactive to Zika virus

“…The DENV envelope (E) protein, considered a major imunodominant target for antibody responses in dengue patients (13)(14)(15), bears greater than 50% homology to ZIKV E protein (16). In addition to complicating the serology-based diagnosis of ZIKV infection, this raises an interesting question about the biological implications of the cross-reactivity on protection, virulence, and immunopathology of ZIKV infections.…”

Live attenuated vaccine: the first clinically approved dengue vaccine?

“…The term 'protective antibodies' is used in this context to differentiate them from 'neutralizing antibodies' as defined by the neutralization assay, which are, as mentioned before, not necessarily protective. The lack of a consistent correlation between cross-neutralization in vitro and cross-protection in vivo is not only observed for polyclonal serum, but also for monoclonal antibodies [2]. However, there is an exception to the rule that serotype-specific antibodies are required for protection: protection can also be achieved in the presence of high titers of cross-neutralizing antibodies for several months after infection [3].…”