Background and Aims: The present study was performed to investigate the effect of Echinops lasiolepis extract on peripheral blood mononuclear cells (PBMCs) proliferation and interferon (IFN)-&gamma secretion.

Materials and Methods: PBMCs were obtained from three healthy volunteers and cultured in presence of Echinops lasiolepis methanol extract in different concentrations of 0.1, 1, 10, 100 and 200 µg/ml. Lipopolysacharide (LPS) and Phytohaemagglutinin (PHA) were considered as mitogen. BrdU cell proliferation assay was used to determine cell proliferation. The concentration of IFN-&gamma in the PBMCs supernatant was determined using enzyme-linked immunosorbent assay.

Results: Most concentrations of Echinops lasiolepis methanol extract showed inhibitory effect on PBMCs proliferation. There were significant differences between the concentrations of 200, 1 and 0.1 µg/ml (p<0.05). The optimum proliferation (30.66±24.67%) was obtained at concentration 1 µg/ml. The PBMCs supernatant IFN-&gamma concentrations in extract treated group without PHA and LPS and in PHA activated group were not significantly different.

Conclusions: Our findings indicated that Echinops lasiolepis extract has immunomodulating activity which may be potentialy to used as an immunotherapy agent.