Esther Morel, J. Germán Herranz-Jusdado, Rocío Simón, Beatriz Abós, Pedro Perdiguero, Alba Martín-Martín, Germán Andrés, Estefanía Muñoz-Atienza, Milagros Guerra Rodriguez, Patricia Díaz-Rosales, Carolina Tafalla, European Commission, Comunidad de Madrid, Morel, Esther, Herranz-Jusdado, J. German, Abós, Beatriz, Perdiguero, Pedro, Martín-Martín, Alba, Muñoz-Atienza, E., Guerra Rodriguez, Milagros, Díaz-Rosales, Patricia, and Tafalla Piñeiro, Carolina
21 Pág., The differentiation of B cells into antibody-secreting cells is fundamental for the generation of humoral immunity. In mammals, this process involves a series of metabolic and intracellular changes, not studied to date in teleost fish, where a clear distinction between naive B cells and plasmablasts/plasma cells (PCs) is still missing. Thus, in the current study, we have established that upon activation, teleost B cells undergo an expansion of the endoplasmic reticulum (ER) but experience no significant changes in mitochondria content. In parallel, the transcription of genes implicated in B cell differentiation increases, while that of mitochondrial genes decreases. In this context, ER monitoring has allowed us to distinguish between small cells with low amounts of ER (FSCloERlo B cells), that correspond to undifferentiated cells, and large cells with expanded ER (FSChiERhi B cells), characterized as plasmablasts. The results shed new light on the B cell differentiation process in teleosts and provide us with novel tools to study B cell function in these species., This work was supported by the European Research Council ( ERC Consolidator Grant 2016 725061 TEMUBLYM ) and by the Comunidad de Madrid (grant 2016-T1/BIO-1672 ). GA was supported by the Amarouto Program for senior scientists from the Comunidad de Madrid .