title: Treatment of Leishmania donovani-infected hamsters with miltefosine: analysis of cytokine mRNA expression by real-time PCR, lymphoproliferation, nitrite production and antibody responses.
abstract: OBJECTIVE
  Miltefosine, an orally effective antileishmanial drug, works directly on the parasite by impairing membrane synthesis and subsequent apoptosis of the parasite and has also been reported to have macrophage-activating functions that aid parasite killing. We investigated the type of immunological responses generated in miltefosine-treated Leishmania donovani-infected hamsters, which simulate the clinical situation of human kala-azar.
  
  
  METHODS
  Twenty-five-day-old infected hamsters, treated with miltefosine at 40 mg/kg for 5 consecutive days, were euthanized on days 30 and 45 post treatment (p.t.) and checked for parasite clearance and for real-time analysis of mRNAs of the Th1/Th2 cytokines interferon-γ (IFN-γ), interleukin-12 (IL-12), tumour necrosis factor-α (TNF-α), inducible nitric oxide synthase (iNOS), IL-4, IL-10 and transforming growth factor-β (TGF-β), nitric oxide (NO) production, the lymphocyte transformation test (LTT) and antibody responses. Responses were compared with the normal and Leishmania-infected groups at the same time points.
  
  
  RESULTS
  By day 45 p.t. there was a significant increase in the mRNA expression of iNOS, IFN-γ, IL-12 and TNF-α, whereas there were significant decreases in IL-4, IL-10 and TGF-β in cured hamsters as compared with their infected counterparts. In vitro stimulation of lymphocytes with concanavalin A and soluble Leishmania donovani antigen showed a maximum LTT response and there was a gradual increase in the NO level (∼7-fold compared with infected counterparts). Anti-Leishmania IgG and IgG1 levels, found to be elevated in the infected group, decreased significantly after treatment but there was a significant increase in IgG2 isotype.
  
  
  CONCLUSIONS
  Treatment of Leishmania-infected hamsters with miltefosine reverses the Th2-type response into a strong Th1-type immune response.
authors: Division of Parasitology,  Central Drug Research Institute, Post Box No. 173, Lucknow-226 001,  India.
authors: Reema
authors: R
authors: Gupta
authors: Pramod K
authors: PK
authors: Kushawaha
authors: Mukesh
authors: M
authors: Samant
authors: Anil K
authors: AK
authors: Jaiswal
authors: Rajendra K
authors: RK
authors: Baharia
authors: Anuradha
authors: A
authors: Dube
mesh_terms: D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood*; D000981:Antiprotozoal Agents / Q000008:administration & dosage; D049109:Cell Proliferation; D006224:Cricetinae; D016207:Cytokines / Q000096:biosynthesis*; D004195:Disease Models, Animal; D007893:Leishmania donovani / Q000187:drug effects / Q000276:immunology*; D007898:Leishmaniasis, Visceral / Q000188:drug therapy* / Q000276:immunology; D008214:Lymphocytes / Q000276:immunology*; D009569:Nitric Oxide / Q000378:metabolism*; D010767:Phosphorylcholine / Q000008:administration & dosage / Q000031:analogs & derivatives*; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D018417:Th1 Cells / Q000276:immunology; D018418:Th2 Cells / Q000276:immunology
chemical_list: D000913:Antibodies, Protozoan; D000981:Antiprotozoal Agents; D016207:Cytokines; D012333:RNA, Messenger; D010767:Phosphorylcholine; D009569:Nitric Oxide; C039128:miltefosine