Evaluation of Adjuvant Effectiveness of Alum-Propranolol Mixture on the Immunogenicity of Excreted/Secreted Antigens of Toxoplasma gondii RH Strain.

Purpose: The introduction of novel adjuvants is an important step in attempts to develop a safe and more efficient vaccine. The present study was performed to determine whether the use of a mixed beta-adrenergic receptor antagonist propranolol (PRP) and aluminum (alum), as an adjuvant, have efficacy for Toxoplasma gondii vaccine to induce protective immunity in a mouse model. Methods: Female BALB/c mice divided into five groups were immunized with excretorys-ecretory antigens (ESA) vaccine, alum-ESA vaccine, PRP-ESA vaccine, and alum-PRP ESA vaccine, as well as with phosphate buffered saline (PBS), as a negative control group. The immune responses were evaluated by lymphocyte proliferation assay for measuring delayedtype hypersensitivity (DTH) response and by cytokine assay for evaluating IFN-γ and IL-5 levels. The survival rate of mice in all groups was assessed during a three-week monitoring period after an intraperitoneal challenge with T. gondii tachyzoites. Results: The results showed that mice immunized with PRP, as an adjuvant, could secret a higher level of IFN-γ, which was significant in comparison to other groups. However, mice vaccinated with alum-precipitated ESA antigen had ability to produce an elevated level of IL-5 compared to other mouse groups (P ≤ 0.05). Moreover, alum-PRP co-administration together with ESA vaccine resulted in the longer survival of mice. Conclusion: The findings of this study revealed that the combination of alum-PRP adjuvants and ESA vaccine of T. gondii elicits both humoral and cellular immune responses, which are comparable to either alum or PRP alone.

Propranolol efficacy as a novel adjuvant for immunization against Toxoplasma gondii tachyzoites.

Severe or lethal damages, caused by Toxoplasma gondii infection in congenital cases and immunocompromised patients implies the necessity for development of a vaccine and an appropriate adjuvant would be needed to elicit a protective Th1 biased-immune response. The adjuvant activity of propranolol was surveyed and compared with alum by immunization of BALB/c mice with protein components of T. gondii tachyzoites. Five groups of BALB/c mice were immunized with phosphate buffered saline (negative control), Toxoplasma lysate antigen (TLA), alum plus TLA, Propranolol plus TLA, and alum, propranolol and TLA. Immunization efficacy was evaluated by lymphocyte proliferation and DTH tests, challenge with live tachyzoites, IFN-γ production by spleen cells, serum TNF-α concentration and anti- Toxoplasma total IgG, IgG1 and IgG2a measurements. Mice of the PRP-TLA group induced significantly more IFN-γ and TNF-α production and lymphocyte proliferation than other groups. This group of mice also showed more anti-T. gondii IgG2a and DTH responses and showed a significantly increased survival time after challenge. These findings indicate that propranolol as an adjuvant in combination with TLA, may enhance cellular immunity against T. gondii.

The Anti-leishmanial Efficacy of Artemisia dracunculus Ethanolic Extract in Vitro and Its Effects on IFN-γ and IL-4 Response.

BACKGROUND: Leishmaniasis is a parasitic disease that appears with a range of symptoms including cutaneous, mucocutaneous, and visceral leishmaniasis. The present study sought to determine the antileishmanial effect of the extract of Artemisia dracunculus (Tarragon) compared to control treatment with pentavalent antimony (meglumine). METHODS: This experimental study was performed in 2014-2015. A. dracunculus were collected from West Azerbaijan Province, Iran and dried; then the ethanolic extract of the plant was prepared. The effect of different concentrations of Artemisia's extract was compared with Glucantime ® in the stationary phase by MTT colorimetric assay and Trypan blue staining. Human peripheral blood mononuclear cells (HPBMCs) treated with L. major and production of IFN-γ and IL-4 cytokines measured at concentrations of 25, 20, 10 and 5µg/ml A. dracunculus. RESULTS: Treatment with the extract did not affect the survival of the parasites during the first 48 h; however, on the third day (72 h), all concentrations significantly reduced the number of parasites with an efficacy of more than 50% at 10 µg/ml (P<0.01), 20µg/ml (P<0.001), and 25 µg/ml (P<0.0001). Moreover, IFN-γ and IL-4 secretion from the HPBMCs was significantly affected in a dose-dependent manner, compared to the control (no extract). The IFN-γ/IL-4 ratio further confirmed this notion. CONCLUSION: A. dracunculus extract cannot only exert potent antileishmanial activity but may also enhance cellular immunity to this parasite. Further studies are required to determine the main compound(s) responsible for these effects of the plant.