The role of platelet microparticles in the production of antibodies from B lymphocytes against HLA-DR antigen in vitro

Background: Platelets can activate B cells and stimulate them for the production of antibodies. Since platelet microparticles (PMPs) originate from platelets, they may have the same virtue. In the present study, the effect of PMPs was investigated on the production of human leukocyte antigen (HLA)-specific antibody from B cells in vitro. Materials and Methods: In this experimental study, HLA-DR antigen was solubilized from the immortalized B lymphocytes (Daudi cell line) and purified using the affinity chromatography. Antigen properties were determined by the ELISA technique. PMPs were isolated from platelet concentrate bags by centrifugation. Fresh blood products were prepared from the Innovation Center of Iranian Blood Transfusion Organization (IBTO) and B lymphocytes were purified by the MACS method. B cells were exposed with PMPs and HLA-DR antigens in the culture medium. On the third day of culture, the culture supernatant was examined in terms of antibody production using the ELISA test. The results were analyzed using paired sample T-test and P-value <0.05 was considered statistically significant. Results: The specificity of the purified HLA-DR antigen was confirmed using the anti-HLA-DR antibody and ELISA technique in the presence of appropriate controls. The results showed that PMPs could stimulate the production of antibodies from B cells. The difference between the case and control was significant (Pvalue= 0.001). Although total immunoglobulin (IgG) was higher in HLA-DR-treated wells, HLA-DR-specific antibodies were not identified by ELISA technique. Conclusion: PMPs have the capability to induce IgG antibodies from B cells. In order to ensure the production of specific antibodies, further testing is required with high sensitivity.