Antibody-mediated humoral immunity is thought to play a central role in mediating the immunopathogenesis of acute?DENV?infection, but limited data are available on the?diversity, specificity, and functionality of the antibody response at the molecular level elicited by?primary?or?secondary?DENV?infection. In order to close this functional gap in our understanding of?DENV-specific humoral immunity, we utilized high-throughput single?cell?RNA sequencing to investigate?B?cells circulating in both?primary?and?secondary?natural?DENV?infections. We captured full-length paired immunoglobulin receptor sequence data from 9,027?B?cells from a total of 6 subjects, including 2,717 plasmablasts. In addi... More
Antibody-mediated humoral immunity is thought to play a central role in mediating the immunopathogenesis of acute?DENV?infection, but limited data are available on the?diversity, specificity, and functionality of the antibody response at the molecular level elicited by?primary?or?secondary?DENV?infection. In order to close this functional gap in our understanding of?DENV-specific humoral immunity, we utilized high-throughput single?cell?RNA sequencing to investigate?B?cells circulating in both?primary?and?secondary?natural?DENV?infections. We captured full-length paired immunoglobulin receptor sequence data from 9,027?B?cells from a total of 6 subjects, including 2,717 plasmablasts. In addition to IgG and IgM class-switched cells, we unexpectedly found a high proportion of the?DENV-elicited plasmablasts expressing IgA, principally in individuals with?primary?DENV?infections. These IgA class-switched cells were extensively hypermutated even in individuals with a serologically confirmed?primary?DENV?infection. Utilizing a combination of conventional biochemical assays and high-throughput shotgun mutagenesis, we determined that?DENV-reactive IgA class-switched antibodies represent a significant fraction of?DENV-reactive Igs generated in response to?DENV?infection, and that they exhibit a comparable epitope specificity to?DENV-reactive IgG antibodies. These results provide insight into the molecular-level?diversity?of?DENV-elicited humoral immunity and identify a heretofore unappreciated IgA?plasmablast?response to?DENV?infection.
