Morel, EstherHerranz Jusdado, J. GermánSimón, RocíoAbós, BeatrizPerdiguero Jiménez, PedroMartín Martín, AlbaAndrés, GermánMuñoz Atienza, EstefaníaGuerra Rodriguez, MilagrosDíaz Rosales, PatriciaTafalla, Carolina2025-09-052025-09-052023-01-20Morel, E., Herranz-Jusdado, J. G., Simón, R., Abós, B., Perdiguero, P., Martín-Martín, A., Andrés, G., Muñoz-Atienza, E., Guerra Rodriguez, M., Díaz-Rosales, P., & Tafalla, C. (2023). Endoplasmic reticulum expansion throughout the differentiation of teleost B cells to plasmablasts. iScience, 26(1). https://doi.org/10.1016/J.ISCI.2022.1058542589-004210.1016/j.isci.2022.105854https://hdl.handle.net/20.500.14352/123726This 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.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.engAttribution-NonCommercial-NoDerivatives 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-nd/4.0/journal articlehttps://doi.org/10.1016/j.isci.2022.105854https://www.sciencedirect.com/science/article/pii/S2589004222021277?via%3Dihubopen access597.2/.5577.2591.1636.09:612.017Biological sciencesMolecular biologyImmunologyZoologíaPecesBiología molecular (Biología)Fisiología animal (Biología)Inmunología veterinaria2401 Biología Animal (Zoología)2415 Biología Molecular2401.13 Fisiología Animal2412 Inmunología