ORIGINAL RESEARCH PAPER Subcutaneous administration CpG-ODNs acts as a potent adjuvant for an HIV-1-tat-based vaccine candidate to elicit cellular immunity in BALB/c mice Zeinab Panahi . Asghar Abdoli . Ghasem Mosayebi . Mehdi Mahdavi . Fariborz Bahrami Received: 28 May 2017 / Accepted: 20 December 2017 Ó Springer Science+Business Media B.V., part of Springer Nature 2018 Abstract Objective To evaluate the combined effects of CpG oligodeoxynucleotides (CpG-ODNs) adjuvant and subcutaneous injection route on efficacy of a HIV-1- tat DNA vaccine candidate using BALB/c mice as an animal model. Results Evaluation of cellular and humoral immu- nity of mice injected subcutaneously with HIV-1-tat gene cloned into a pcDNA3.1 vector indicated that significant levels of IFN-c cytokine secretion (900 pg/ ml), lymphocyte proliferation (2.5 stimulation index) and IgG 2a (1.45 absorbance 450 nm) production could be achieved. These indicators of stimulated cellular immunity were elicited 2 weeks after the last injection (P \ 0.05). Conclusions Formulation of HIV-1-tat DNA vac- cine candidate with CpG-ODNs as an adjuvant while administrated subcutaneously are a promising approach to induce effective cellular immunity responses against HIV-1 infection. Keywords CpG-ODNs Á DNA vaccine Á HIV-1 Á Subcutaneous injection Á Tat Á HIV vaccine Introduction An approach to design vaccines against HIV-1 infec- tion is to use the modulator genes of the virus to induce immune responses that could either prevent the infection or block virus replication. An effective vaccine against HIV-1 must induce both humoral and cellular immunities to prevent HIV-1 infection of the portal routes and the consequent progression of the disease towards acquired immune deficiency syn- drome (AIDS). There is growing evidence that DNA vaccines incorporating HIV trans-activator of tran- scription gene (tat) can induce a significant antibody titer against Tat protein that then enhances responses of proliferative lymphocytes (Caputo et al. 2009; Chihana et al. 2015; Cohen and Dolin 2013; Rosen and Fox 2011). Furthermore, compared to a partial Tat protein, whole Tat protein gives better results for stimulating the immune responses (Caputo et al. 2009). To improve the efficacy of vaccines, combining the vaccine with an appropriate adjuvant is a critical factor Z. Panahi Á G. Mosayebi (&) Department of Microbiology and Immunology, School of Medicine, Molecular and Medicine Research Center (MMRC), Arak University of Medical Sciences, P.O. Box: 38481-7-6941, Arak, Iran e-mail: ghasemmosayebi@arakmu.ac.ir; gmosayebi@yahoo.com A. Abdoli Department of Hepatitis and AIDS, Pasteur Institute of Iran, Tehran, Iran M. Mahdavi Á F. Bahrami Department of Immunology, Pasteur Institute of Iran, Tehran, Iran 123 Biotechnol Lett https://doi.org/10.1007/s10529-017-2497-9