Abstract

Background: Although antibiotics are well-known for their anti-bacterial effects, their inaugurated immunomodulatory roles in chronic inflammatory diseases have not elucidated yet. Anecdotal reports support the beneficial effects of parenteral penicillin in arthritis suggesting an immunomodulatory other than antibacterial effects for penicillin. The present study was designed to address the possible effects of penicillin G sodium (PCN-G) on different T-helper cells differentiation. Materials and Methods: In this experimental study, peripheral blood mononuclear cells (PBMCs) of 10 healthy donors were isolated using Ficoll density gradient. The stimulated PBMCs by anti-CD3, anti-CD28, and anti-CD69 were cultured in the presence of 120 mu g/ml of PCN-G. Foxp3, T-bet, ROR gamma T, GATA3 as well as interferon-gamma (IFN-gamma) and interleukin (IL)-17A mRNA in stimulated cells were measured by the real-time polymerase chain reaction. Mann-Whitney U-test was used for determining differences between the medium of gene expression levels of stimulated cell population and unstimulated cells by PCN. Correlations between the related genes were determined using the Spearman test. Results: Based on the results, T-bet gene expression levels were similar in stimulated cells by PCN G after 24 and 48 h while significant reduction was observed after 72 incubation with PCN G (difference = 3; 0.09-0.34; P = 0.031). Meanwhile, treated cells with PCN G expressed decreased levels of IFN-gamma (difference = 8.0; 0.49-1.07; P = 0.001) and IL-17A (difference = 2.2; 0.05-0.75; P <= 0.05) genes comparing to unstimulated cell by PCN-G. GATA3 genes expression levels downregulated by PCN G after 72 h of incubation by PBMCs (difference = 1.1; 0.77-0.88; P = 0.035). Conclusion: Our results confirmed the immunomodulatory role of PCN G by affecting the expression of different cytokines genes in PBMCs.