Please use this identifier to cite or link to this item:http://hdl.handle.net/20.500.12105/16838
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
Int J Mol Sci. 2023 Sep 6;24(18):13754.
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.
HIV Infections | Pneumococcal Infections | Humans | Memory B Cells | Streptococcus pneumoniae | Adjuvants, Immunologic | Complementarity Determining Regions | Immunoglobulin M
- Investigación > IIS > IIS BioBizkaia - Asociación Instituto de Investigación Sanitaria BioBizkaia (País Vasco)
- Investigación > IIS > IIS BioGipuzkoa - Asociación Instituto de Investigación Sanitaria BioGipuzkoa (País Vasco)
- Investigación > IIS > IBIS - Instituto de Biomedicina de Sevilla (Andalucía)
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