ABSTRACT
Memory B cells (mBCs) are characterized by their long-term stability, fast reactivation, and capability to rapidly differentiate into antibody-secreting cells (ASCs). However, the role of T cells in the differentiation of mBCs, in contrast to naive B cells, remains to be delineated. We study the role of T cells in mBC responses, using CD40L stimulation and autologous T-B co-cultures. Our results showed that increased CD40L levels led to a selective increased proliferation of IgM+ mBC, which did not class-switched, resulting in higher frequencies of IgM+ ASCs and a lower frequency of IgG+ ASCs. The IgG+/IgA+ mBCs were unaffected. We further compared the transcription of immune-related genes in IgM+ and IgG+ pre-plasmablasts cultured at high (500 ng/mL) and low (50 ng/mL) CD40L levels. In response to increased CD40L levels, both populations exhibited a core response to genes related to activation (TRAF1, AKT3, CD69, and CD80). However, they differed in genes related to cytokine/chemokine/homing interactions (CCL3/4/17, LTA, NKX2-3, BCL2 and IL21R) and cell-cell interactions (HLADR, CD40, and ICOSL), which were largely confined to IgG+ cells. Our findings revealed that in co-cultures with a high T-ratio, the response was similar to that found in cultures with high CD40L levels. These results suggest that IgG+ mBCs have a greater capacity for proliferation and T cell interaction, and weaker migration capabilities, leading to a preference for an IgG response over IgM in the short term. This adaptable response could fine-tune the memory repertoire with different functions of IgG versus IgM mBCs.
Subject(s)
CD40 Ligand , Immunoglobulin G , Immunoglobulin M , Memory B Cells , T-Lymphocytes , CD40 Ligand/metabolism , CD40 Ligand/immunology , Humans , Immunoglobulin M/immunology , Immunoglobulin M/metabolism , Immunoglobulin G/immunology , T-Lymphocytes/immunology , T-Lymphocytes/metabolism , Memory B Cells/immunology , Memory B Cells/metabolism , Cell Communication/immunology , Coculture Techniques , Immunologic Memory , Lymphocyte Activation/immunology , Cells, Cultured , Cell Differentiation/immunology , Cell ProliferationABSTRACT
Salvia hispanica L. (Lamiaceae) -conocida como "chía"- es una especie de interés dietario-medicinal, fuente de ácidos grasos omega-6 y omega-3, proteínas, antioxidantes y fibras solubles e insolubles. Con el objetivo de caracterizar harinas de S. hispanica que se comercializan en la ciudad de Rosario, se analizaron muestras adquiridas en diferentes comercios. Se realizó la caracterización botánica y se determinó: fibras brutas totales, humedad, cenizas, proteínas y ácidos grasos. Las muestras comercializadas como harina corresponden, en realidad, a semillas de "chía" molidas. Se comprobó que existen a la venta lotes de harina de "chía" de los que se desconoce su procedencia y procesamiento, algunos adulterados con semillas de otras especies. Los resultados de humedad y de proteínas obtenidos estuvieron dentro de los valores estipulados por el Código Alimentario Argentino 2009 pero ciertos valores de fibra bruta total y ceniza fueron inferiores. Con este relevamiento se comprobó que lo comercializado como harina de "chía" en la ciudad de Rosario es semilla molida, donde se observa una alta variación en la calidad, pues se dispone en el mercado desde productos de alta pureza hasta otros, totalmente adulterados.