Monosodium glutamate induces apoptosis in naive and memory human B cells

The aim of this study was to establish the existence of mGluR7 in normal B lymphocytes and analyse the effect of monosodium glutamate (MSG) on B cell apoptosis in vitro. B cells were purified by magnetic cell sorting using anti-CD19-coupled magnetic beads. Cells (10(6)/ml) were cultured with increasing MSG concentrations (1-100 mM). Detection of apoptosis by flow cytometry was performed using the Annexin V-FITC/Propidium iodide (PI) apoptosis detection kit. Naïve and memory B cell population were identified by CD27 staining. Expression of GluRs was determined using PCR. Exposure to increasing MSG concentrations displayed dose dependent effect on B cell viability altogether, ranging from 35% with 100 mM up to 80% with 1 mM MSG. Moreover, the number of late apoptotic cells as well as necrotic cells was dose dependant. Both CD27- as well as CD27+ B cells were affected by MSG. Basal expression of GluRs7 was detected in unstimulated B cells. Glutamate induced apoptosis can be seen in memory as well as naive B cell population and is probably mediated through mGluR7, whose expression in B cells we also confirmed. Our study suggests a new possible mechanism of crosstalk between the nervous and the immune system through glutamate as a potential key mediator (Fig. 4, Ref. 27). Full Text (Free, PDF) www.bmj.sk.