Abstract

MADRID, Melissa; RESTREPO, Paula A.  and  TRUJILLO-VARGAS, Claudia M.. Differential expression of LRBA protein in human naive and memory B lymphocytes. Actu Biol [online]. 2020, vol.42, n.112, e5. ISSN 0304-3584.  https://doi.org/10.17533/udea.acbi/v42n112a05.

LRBA deficiency (Lipopolysaccharide-responsive and beige-like anchor protein) is a primary immunodeficiency caused by a defective expression of the intracellular protein LRBA, due to homozygous and heterozygous composed mutations in the corresponding gene. Patients with this immunodeficiency have a wide spectrum of clinical manifestations that include mainly immunodeficiency and autoimmunity. LRBA deficiency is associated with a decrease in class-switched memory B cells in peripheral blood and plasmablasts count, and a specific antibody response defective, as well as a defect in apoptosis and autophagy. In this study, intracellular differential expression of the LRBA protein in naïve and memory B cells of human peripheral blood was evaluated under different conditions by flow cytometry. We evidence that memory B cells have a higher expression of LRBA; on the other hand, we demonstrate that the expression of this protein in the B cells increases considerably under activation conditions; however; the magnitude of the increase in LRBA expression under this condition is higher in naïve B cells. In contrast, we show that the expression of this protein decreases in B cells undergoing to apoptosis, although even under these conditions, it is higher in memory B cells. These findings suggest that LRBA plays an important role in the development of humoral immune memory.

Keywords : Apoptosis; flow cytometry; primary immunodeficiency diseases; naïve B cells; memory B cells; proliferation assays.

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