2026-07-21T11:34:06Zhttps://repisalud.isciii.es/rest/oai/request

oai:repisalud.isciii.es:20.500.12105/168382025-04-24T11:27:52Zcom_20.500.12105_2052com_20.500.12105_2051com_20.500.12105_15322col_20.500.12105_19609col_20.500.12105_16958col_20.500.12105_16976col_20.500.12105_16974

00925njm 22002777a 4500 dc Vitallé, Joana author Zenarruzabeitia, Olatz author Merino-Pérez, Aitana author Terrén, Iñigo author Orrantia, Ane author Pacho de Lucas, Arantza author Iribarren, José Antonio author García-Fraile, Lucio Jesús author Balsalobre, Luz author Amo, Laura author Andres, Belen de author Borrego, Francisco author 2023-09-06 CD300a is differentially expressed among B cell subsets, although its expression in immunoglobulin (Ig)M+ B cells is not well known. We identified a B cell subset expressing CD300a and high levels of IgM (IgMhiCD300a+). The results showed that IgMhiCD300a+ B cells were CD10-CD27+CD25+IgDloCD21hiCD23-CD38loCD1chi, suggesting that they are circulating marginal zone (MZ) IgM memory B cells. Regarding the immunoglobulin repertoire, IgMhiCD300a+ B cells exhibited a higher mutation rate and usage of the IgH-VDJ genes than the IgM+CD300a- counterpart. Moreover, the shorter complementarity-determining region 3 (CDR3) amino acid (AA) length from IgMhiCD300a+ B cells together with the predicted antigen experience repertoire indicates that this B cell subset has a memory phenotype. IgM memory B cells are important in T cell-independent responses. Accordingly, we demonstrate that this particular subset secretes higher amounts of IgM after stimulation with pneumococcal polysaccharides or a toll-like receptor 9 (TLR9) agonist than IgM+CD300a- cells. Finally, the frequency of IgMhiCD300a+ B cells was lower in people living with HIV-1 (PLWH) and it was inversely correlated with the years with HIV infection. Altogether, these data help to identify a memory B cell subset that contributes to T cell-independent responses to pneumococcal infections and may explain the increase in severe pneumococcal infections and the impaired responses to pneumococcal vaccination in PLWH. Int J Mol Sci. 2023 Sep 6;24(18):13754. 10.3390/ijms241813754 1422-0067 International journal of molecular sciences 37762055 http://hdl.handle.net/20.500.12105/16838 CD300 CD300a IgM IgD B cell Memory Marginal zone Pneumococcus Polysaccharides HIV Human IgMhiCD300a+ B Cells Are Circulating Marginal Zone Memory B Cells That Respond to Pneumococcal Polysaccharides and Their Frequency Is Decreased in People Living with HIV