Immunomodulatory Effect of Allogenic Bone Marrow-derived Mesenchymal Stem Cells on Salmonella-derived Flagellin

Mesenchymal stem cell (MSC) research has become increasingly important because of the multipotent nature of MSCs. They have been found to have immunomodulatory effects both in vitro and in vivo. The present study was designed with the objective to compare the effect of proliferating and non-proliferating allogenic bone marrow-derived MSCs on antibody production using bacterial flagellin as the model antigen. A total of 36 mice were randomly divided into six groups (6/group) and was immunised with mitomycin C treated (non-proliferating) or untreated allogenic MSCs with or without antigen, while PBS and antigen received group were kept as control. Immunisation was done on 0, 7, 14, 21 days by the intraperitonial route and serum was collected at weekly intervals for up to 5^th week postimmunisation to evaluate the antibody response detected by ELISA. In the present study, the highest antibody response was recorded in the group, which received antigen along with non-proliferating MSC and differed significantly (1.704±0.070) by the group which received antigen along with proliferating MSC (1.606±0.089) (P<0.05). Moreover, the group of mice which received antigen alone could not exhibit higher antibody response (1.289±0.029); rather the values were sufficiently low. Thus, the present study revealed that MSCs are stimulatory to B cells by antibody secretion, rather than by suppressive effect.