title: Role of pro-inflammatory cytokine IL-17 in Leishmania pathogenesis and in protective immunity by Leishmania vaccines.
abstract: The clinical outcome of Leishmania pathogenesis ranges from active skin lesions to fatal visceral dissemination and severely impaired T cell immunity. It is well established that a strong Th1 immune response is protective against cutaneous forms of the disease, however a mixed Th1/Th2 response is most commonly observed against visceral infections as evident from previous studies. Aside from Th1/Th2 cytokines, the pro-inflammatory IL-17 cytokine family plays an important role in the clearance of intracellular pathogens. In Leishmania induced skin lesions, IL-17 produced by Th17 cells is shown to exacerbate the disease, suggesting a role in pathogenesis. However, a protective role for IL-17 is indicated by the expansion of IL-17 producing cells in vaccine-induced immunity. In human visceral leishmaniasis (VL) it has been demonstrated that IL-17 and IL-22 are associated with protection against re-exposure to Leishmania, which further suggests the involvement of IL-17 in vaccine induced protective immunity. Although there is no vaccine against any form of leishmaniasis, the development of genetically modified live attenuated parasites as vaccine candidates prove to be promising, as they successfully induce a robust protective immune response in various animal models. However, the role of IL-17 producing cells and Th17 cells in response to these vaccine candidates remains unexplored. In this article, we review the role of IL-17 in Leishmania pathogenesis and the potential impact on vaccine induced immunity, with a special focus on live attenuated Leishmania parasites.
authors.affiliation: Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD, USA.
authors.forename: Antara
authors.initials: A
authors.lastname: Banerjee
authors.affiliation: Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD, USA.
authors.forename: Parna
authors.initials: P
authors.lastname: Bhattacharya
authors.affiliation: Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD, USA.
authors.forename: Amritanshu B
authors.initials: AB
authors.lastname: Joshi
authors.affiliation: Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD, USA.
authors.forename: Nevien
authors.initials: N
authors.lastname: Ismail
authors.affiliation: Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD, USA. Electronic address: Ranadhir.Dey@fda.hhs.gov.
authors.forename: Ranadhir
authors.initials: R
authors.lastname: Dey
authors.affiliation: Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, MD, USA. Electronic address: Hira.Nakhasi@fda.hhs.gov.
authors.forename: Hira L
authors.initials: HL
authors.lastname: Nakhasi
mesh_terms: D000818:Animals; D006801:Humans; D007111:Immunity, Cellular; D020381:Interleukin-17 / Q000378:metabolism*; D007891:Leishmania / Q000276:immunology*; D007896:Leishmaniasis / Q000276:immunology*; D054332:Leishmaniasis Vaccines / Q000276:immunology*; D058408:Th1-Th2 Balance; D058504:Th17 Cells / Q000276:immunology*; D014613:Vaccines, Attenuated
chemical_list: D020381:Interleukin-17; D054332:Leishmaniasis Vaccines; D014613:Vaccines, Attenuated
keywords: IL-17; Leishmania; Th17 cells; Vaccine