RT Journal Article SR Electronic T1 MicroRNA-155 is essential for the optimal proliferation and survival of plasmablast B cells JF Life Science Alliance JO Life Sci. Alliance FD Life Science Alliance LLC SP e201800244 DO 10.26508/lsa.201800244 VO 2 IS 3 A1 Arbore, Giuseppina A1 Henley, Tom A1 Biggins, Laura A1 Andrews, Simon A1 Vigorito, Elena A1 Turner, Martin A1 Leyland, Rebecca YR 2019 UL http://www.life-science-alliance.org/content/2/3/e201800244.abstract AB A fast antibody response can be critical to contain rapidly dividing pathogens. This can be achieved by the expansion of antigen-specific B cells in response to T-cell help followed by differentiation into plasmablasts. MicroRNA-155 (miR-155) is required for optimal T-cell–dependent extrafollicular responses via regulation of PU.1, although the cellular processes underlying this defect are largely unknown. Here, we show that miR-155 regulates the early expansion of B-blasts and later on the survival and proliferation of plasmablasts in a B-cell–intrinsic manner, by tracking antigen-specific B cells in vivo since the onset of antigen stimulation. In agreement, comparative analysis of the transcriptome of miR-155–sufficient and miR-155–deficient plasmablasts at the peak of the response showed that the main processes regulated by miR-155 were DNA metabolic process, DNA replication, and cell cycle. Thus, miR-155 controls the extent of the extrafollicular response by regulating the survival and proliferation of B-blasts, plasmablasts and, consequently, antibody production.