Garlic induces a shift in cytokine pattern in Leishmania major-infected BALB/c mice
The regulation of T helper (Th)1- and Th2-type cytokine patterns is important in the final outcome of leishmaniasis in human and murine models. We examined the efficacy of garlic therapy or a combination of garlic and an antimonial drug (glucantime) in promoting healing and regulation of Th1/Th2 cytokine patterns in highly susceptible BALB/c mice infected with Leishmania major. Separate groups of infected mice received 20 mg/kg/day garlic, 60 mg/kg/day glucantime or a combination of the two, from day 30 after infection for 2 weeks. An enzyme-linked immunosorbant assay (ELISA) was performed on spleen cell culture supernatants for interferon(IFN)-gamma interleukin(IL)-2, IL-4 and IL-10. The results indicate that garlic therapy is more effective than the usual antileishmanial drug in curing the infection. Garlic-treated mice developed Th1-type cytokine responses. In contrast, glucantime therapy led to a Th2-type response in the control group with a lower level of IL-2. However, a combination of garlic and glucantime treatment was more effective than either treatment alone, and resulted in a Th1-type response similar to that which developed with garlic treatment. These results suggest that garlic extract in combination with an antimonial drug, may provide effective therapy against L. major. The immunomodulatory properties of garlic were elucidated in terms of shifting the cytokine response to a Th1-type pattern and therefore causing the protective response.