Treatment of Leishmania donovani-infected hamsters with miltefosine: analysis of cytokine mRNA expression by real-time PCR, lymphoproliferation, nitrite production and antibody responses

• Published in: Journal of antimicrobial chemotherapy 2012-02, Vol.67 (2), p.440-443
• Main Authors: GUPTAT, Reema, KUSHAWAHAT, Pramod K, SAMANT, Mukesh, JAISWAL, Anil K, BAHARIA, Rajendra K, DUBE, Anuradha
• Format: Article
• Language: English
• Subjects: Animals; Antibiotics. Antiinfectious agents. Antiparasitic agents; Antibodies, Protozoan - blood; Antimicrobial agents; Antiprotozoal Agents - administration & dosage; Apoptosis; Bacterial infections; Biological and medical sciences; Cell Proliferation; Concanavalin A; Cricetinae; Cytokines; Cytokines - biosynthesis; Disease Models, Animal; Drugs; Effectiveness studies; gamma -Interferon; Gene expression; Helper cells; Hematologic and hematopoietic diseases; Human protozoal diseases; Immune response; Immunoglobulin G; Infectious diseases; Interleukin 10; Interleukin 12; Interleukin 4; Leishmania donovani; Leishmania donovani - drug effects; Leishmania donovani - immunology; Leishmaniasis, Visceral - drug therapy; Leishmaniasis, Visceral - immunology; Leshmaniasis; Leukemias. Malignant lymphomas. Malignant reticulosis. Myelofibrosis; Lymphocyte transformation; Lymphocytes - immunology; Lymphocytes T; Medical sciences; Miltefosine; Nitric oxide; Nitric Oxide - metabolism; Nitric-oxide synthase; Nitrite; Parasites; Parasitic diseases; Pharmacology. Drug treatments; Phosphorylcholine - administration & dosage; Phosphorylcholine - analogs & derivatives; Polymerase chain reaction; Protozoal diseases; Real-Time Polymerase Chain Reaction; RNA, Messenger - analysis; RNA, Messenger - genetics; Rodents; Th1 Cells - immunology; Th2 Cells - immunology; Transforming growth factor- beta; Tumor necrosis factor- alpha
• ISSN: 0305-7453; 1460-2091
• DOI: 10.1093/jac/dkr485

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. 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. 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. Treatment of Leishmania-infected hamsters with miltefosine reverses the Th2-type response into a strong Th1-type immune response.