Methanolic Extract of Teucrium Polium Exerts Immunomodulatory Properties in Human Peripheral Blood Mononuclear Cells

Teucrium polium has been used in traditional medicine around the world for centuries in treatment of various conditions and diseases. Many studies have confirmed pharmacological effects of its extracts, although the immunomodulatory effect has not been investigated. Therefore, the aim of our study was to examine the immunomodulatory effect of methanolic extract of T. polium (TPE) on peripheral blood mononuclear cells (PBMCs) derived from healthy donors and patients with hepatitis C virus HCV infection. We analyzed the effect of the extract on PBMCs viability using the MTT test. The cell death type was determined using Annexin V-FITC/7-AAD staining. Immunophenotyping using anti-CD8 FITC, anti-CD4 PE, anti-CD3 ECD, anti-CD20 PC5, anti-CD14 FITC and anti-CD25 PC7 was performed by flow cytometry. Results of the MTT test indicate that TPE stimulates proliferation of healthy PBMCs, while the HCV PBMCs viability was slightly reduced. The percentage of apoptotic HCV PBMCs was higher after TPE treatment compared to the control. The proportion of CD25-expressing cells was higher among the untreated HCV PBMCs than in the untreated healthy PBMCs. TPE treatment significantly and gradually increased CD25 expression in healthy PBMCs, whereas CD25 expression on HCV PBMCs increased only at the highest TPE concentration. The upregulation of double-positive CD3+CD25+, CD20+CD25+ and CD14+CD25+ cells was significant in TPE treated healthy PBMCs, while only the highest concentration was effective on HCV PBMCs. In summary, TPE exerts a strong immunomodulatory effect on healthy PBMCs and, only at the highest concentration, on HCV PBMNCs.