Combinations of Iranian propolis and Leishmania proteins have the potential to influence IL-4 and IFN-γ in immunized Balb/c mice

Abstract

This study seeks to evaluate the effects of Iranian green propolis (IGP) and Leishmania heat shock protein (HSP) 70 as adjuvants, each combined with Leishmania glycoprotein (Gp) 63 as an antigen, on the immune responses in Balb/c mice, in order to develop a new vaccine formulation against Leishmania parasites. Forty-four Balb/c mice were divided into six groups, each inoculated subcutaneously with normal saline (NS): Gp63, Gp63 plus IGP, IGP, HSP70 and HSP70 plus Gp63. Splenic mononuclear cells (sMCs) were isolated from immunized mice and treated with 50 µg of IGP, HSP70, Gp63 and soluble Leishmania antigen (SLA). Afterwards the levels of IL-4 and IFN-γ were measured by ELISA method. The results showed that IGP was a potent inducer of IL-4 and IFN-γ from sMCs of almost all mice groups. When sMCs of the mice immunized with Gp63 in combination with IGP and HSP70, were treated with SLA, the level of IFN-γ was significantly up-regulated, compared with that in NS treated sMCs. In addition, the level of IFN-γ in response to SLA was significantly higher in the mice immunized with Gp63 plus HSP70, compared with that in Gp63. These findings revealed that IGP has the potency to stimulate both the humoral and cellular arms of the immune system. Furthermore, in combination with Gp63, IGP showed similar potency to HSP70 in the induction of IFN-γ, which is an effective defense against intracellular Leishmania parasites. In conclusion, immuno-modulatory effects of IGP make it an attractive adjuvant for Leishmania vaccine development.