Contents lists available at ScienceDirect Molecular Immunology journal homepage: www.elsevier.com/locate/molimm Immunomodulation induced through ornithine decarboxylase DNA immunization in Balb/c mice infected with Leishmania donovani Akhilesh Kumar a,1 , Manas Ranjan Dikhit b,1 , Ajay Amit a , Amir Zaidi c , Raj Kishor Pandey a,d , Ashish kumar Singh a , Shashi S. Suman c , Vahab Ali c , Vidya Nand Rabi Das e , Krishna Pandey e , Vikas kumar a , Shubhankar Kumar Singh f , Shyam Narayan f , Hirendra kumar Chourasia g , Pradeep Das h , Sanjiva Bimal a, ⁎ a Division of Immunology, Rajendra Memorial Research Institute of Medical Sciences, Patna 800007, India b Dept. of Biomedical Informatics, Rajendra Memorial Research Institute of Medical Sciences, Agamkuan, Patna 800007, India c Laboratory of Molecular Biochemistry and Cell Biology, Department of Biochemistry, Rajendra Memorial Research Institute of Medical Sciences, Agamkuan, Patna 800007, India d Department of Biotechnology, National Institute of Pharmaceutical Education and Research, EPIP Complex, Hajipur 844102, India e Dept. of Clinical Medicine, Rajendra Memorial Research Institute of Medical Sciences, Patna 800007, India f Division of Microbiology, Rajendra Memorial Research Institute of Medical Sciences, Patna 800007, India g P.G Department of Biotechnology, TM Bhagalpur University, Bhagalpur 812007, India h Dept. of Molecular Biology, Rajendra Memorial Research Institute of Medical Sciences, Patna 800007, India ARTICLE INFO Keywords: Visceral leishmaniasis Ornithine decarboxylase Interferon-gamma Tumor necrosis factor alpha Interleukin-12 Carboxy fluorescein succinimidyl ester ABSTRACT We report here a Leishmania donovani ornithine decarboxylase (Ld-ODC) gene used as a DNA vaccine against visceral leishmaniasis in a murine Balb/c mouse model. This study also evaluated the possible mechanism of action directed by this candidate. We found a Th1 immune response after immunization using an Ld-ODC DNA vaccine, with results based on the rearrangement of TCR-V-α-2, proliferation of Carboxy fluorescein Succinimidyle ester positive T cells, which were able to produce cytokines such as TNF-α, IFN-γ, IL-12 and IL-2, but not IL-4, IL-5, IL-6 and IL-10, and modulations of the STAT-1 and p38 MAP kinase signaling pathways. The results were corroborated with the reduction in the amastigote proliferation and parasite killing in spleens after infection in vitro. We conclude this study suggesting that the Ld-ODC DNA construct could be a new vaccine candidate against visceral leishmaniasis. 1. Introduction Infection with Leishmania, a protozoan pathogen in humans, leads to different clinical forms of leishmaniasis, such as cutaneous leishma- niasis (CL), muco-cutaneous leishmaniasis (MCL), and visceral leish- maniasis (VL). Of these forms, VL can progress to a fatal outcome if left untreated (Desjeux, 2004; Roque and Jansen, 2014; Dikhit et al., 2017a). A majority of the existing drugs used to treat VL are fraught with limitations such as cost, toxicity, and resistance (Sundar et al., 1997; Abdo et al., 2003; Das et al., 2005; Singh et al., 2016; Amit et al., 2017a; Mansuri et al., 2017). Although vaccines against canine visceral leishmaniasis are available, no vaccine is available for human visceral leishmaniasis and such chemotherapy remains the mainstay of control of this parasite (Singh et al., 2016; Amit et al., 2017a; Dikhit et al., 2016a, 2017b, 2018). Thus, an immediate need exists to identify the potential targets of Leishmania and their screening in the immuno- prophylaxis program against VL. During the mammalian phase of the life cycle of Leishmania, try- panothione synthase {T (SH) 2 } is abundantly present in the parasite, which can be utilized by Leishmania spp. for growth and virulency (Légaré et al., 2001; Dey et al., 1996). The major thrust of research for the control of Leishmaniasis is to either inhibit essential transporters or block some vital metabolic pathways in the parasites (Guha et al., 2013). Therefore, regulation through appropriate interference in the {T (SH) 2 } pathway can provide clues for effective vaccine development against VL. Leishmania strains showing frequent gene amplification to trigger ATP transporter proteins (ATP S ) have been reported. These strains confer resistance to many anti-leishmanial drugs by the se- questration of trypanothione {T (SH) 2 }(Dey et al., 1996). Despite the wealth of existing data on the survival strategy of https://doi.org/10.1016/j.molimm.2018.03.004 Received 24 November 2017; Received in revised form 5 March 2018; Accepted 7 March 2018 ⁎ Corresponding author at: Div. of Immunology, Rajendra Memorial Research Institute of Medical Sciences, Indian Council of Medical Research, Agamkuan, Patna 800007, India. 1 These authors contributed equally to this work. E-mail addresses: drsbimal24@yahoo.com, drsanjiba.rmri@gmail.com (S. Bimal). Molecular Immunology 97 (2018) 33–44 0161-5890/ © 2018 Elsevier Ltd. All rights reserved. T