Appanna R, Kg S, Xu MH, Toh YX, Velumani S, Carbajo D, Lee CY, Zuest R, Balakrishnan T, Xu W, Lee B, Poidinger M, Zolezzi F, Leo YS, Thein TL, Wang CI, Fink K. Plasmablasts During Acute Dengue Infection Represent a Small Subset of a Broader Virus-specific Memory B Cell Pool.
EBioMedicine 2016;
12:178-188. [PMID:
27628668 PMCID:
PMC5078588 DOI:
10.1016/j.ebiom.2016.09.003]
[Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 08/25/2016] [Accepted: 09/06/2016] [Indexed: 01/12/2023] Open
Abstract
Dengue is endemic in tropical countries worldwide and the four dengue virus serotypes often co-circulate. Infection with one serotype results in high titers of cross-reactive antibodies produced by plasmablasts, protecting temporarily against all serotypes, but impairing protective immunity in subsequent infections. To understand the development of these plasmablasts, we analyzed virus-specific B cell properties in patients during acute disease and at convalescence. Plasmablasts were unrelated to classical memory cells expanding in the blood during early recovery. We propose that only a small subset of memory B cells is activated as plasmablasts during repeat infection and that plasmablast responses are not representative of the memory B cell repertoire after dengue infection.
Antibody sequences and functions were analyzed in longitudinal acute and convalescent samples from dengue patients
Plasmablast antibodies were virus glycoprotein-specific whereas memory B cell-derived antibodies bound to more viral proteins
plasmablasts seem to be activated from only a small subset of memory B cells
Antibody-mediated immune memory is orchestrated by various B cell types that are relevant during different phases after an infection. Antibody-secreting cells or so-called plasmablasts are generated from activated specific memory B cell a few days after re-infection. However, little in known whether the antibodies produced by these plasmablasts are relevant for protection in humans and whether the parent memory B cells are further maintained in the memory pool, possibly as affinity-matured versions of the original clones. This is important in the context of vaccination since the repertoires of individual B cell subsets could represent biomarkers to assess efficacy and long-term protection. In addition, the generation of “protective” B cell subsets could potentially be influenced by vaccine design and by the use of adjuvants.
We studied the relationship of plasmablasts and memory B cells in longitudinal blood samples from dengue patients. Dengue virus (DENV) has four serotypes and pre-existing antibodies can be cross-protective or can enhance disease after a heterologous infection via Fc-gamma-receptor-mediated uptake of virus-antibody complexes. B cell memory can therefore be both beneficial and detrimental. Here we studied plasmablasts and DENV-specific memory B cells and their relationship and protective potential by assessing antibody sequences and monoclonal antibodies. We found that both populations produced largely serotype cross-neutralizing antibodies, whereas more plasmablast antibodies were neutralizing. Few plasmablast clones could be found in the memory pool, suggesting that only a subset of memory B cells is activated during acute disease and that a separate repertoire of cells is retained as longer-term memory. In this study we started to dissect the complexity of B cell immune memory to dengue infection and the finding can inform further investigations into which immune cell subsets are disease-enhancing after a heterologous infection.
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