Prophylactic interferon-γ and interleukin-17 facilitate parasite clearance in experimental visceral leishmaniasis.

Background And Objective: The synergy of interleukin (IL)-17 along with other pro-inflammatory cytokines is well known in various autoimmune and infectious diseases. A longitudinal study in the Sudanese population showed an association of IL-17 with the protection of kala-azar outbreak. The protective role of IL-17 is also known in terms of expansion of IL-17-producing cells in vaccine-induced immunity. However, the prophylactic role of IL-17 in visceral leishmaniasis has still not been validated. In the present study, we evaluated the prophylactic efficacy of IL-17A and interferon (IFN)-γ in -challenged Balb/c mice.

Materials And Methods: Two doses of recombinant IL (rIL)-17A and/or IFN-γ were administered intraperitoneally after/at 1 week interval and then the mice were challenged with amastigote form of . At 45 days of postchallenge, mice were sacrificed and evaluated for change in the body and organ weight, parasitic load in visceral organs, and fold change in gene expression of cytokines.

Results: We observed that the prophylactic use of rIL-17A and IFN-γ alone or in combination significantly inhibited the parasitic load in visceral organs. Furthermore, pro-inflammatory cytokine gene expression increased up to 2-4-folds in mice treated with recombinant cytokines.

Conclusion: Our results suggest that prophylactic use of recombinant IFN-γ and IL-17A inhibits parasitic growth in visceral organs of -challenged experimental mice model, especially through upregulation of pro-inflammatory cytokines' gene expression.