PT - JOURNAL ARTICLE AU - Arbore, Giuseppina AU - Henley, Tom AU - Biggins, Laura AU - Andrews, Simon AU - Vigorito, Elena AU - Turner, Martin AU - Leyland, Rebecca TI - MicroRNA-155 is essential for the optimal proliferation and survival of plasmablast B cells AID - 10.26508/lsa.201800244 DP - 2019 Jun 01 TA - Life Science Alliance PG - e201800244 VI - 2 IP - 3 4099 - http://www.life-science-alliance.org/content/2/3/e201800244.short 4100 - http://www.life-science-alliance.org/content/2/3/e201800244.full SO - Life Sci. Alliance2019 Jun 01; 2 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.