Vaccine 24 (2006) 2790–2798 Nonclinical toxicology study of recombinant-plasmid DNA anti-rabies vaccines P. Uday Kumar a , B. Dinesh Kumar a , V.V. Annapurna a , T. Prasanna Krishna a , S. Kalyanasundaram a , P. Suresh a , N. Harishankar a , V. Jagadeesan a , S. Hariharan a , A. Nadamuni Naidu a , Kamala Krishnaswamy a , P.N. Rangarajan b , V.A. Srinivasan c , G.S. Reddy c , B. Sesikeran a,∗ a National Institute of Nutrition, (Indian Council of Medical Research), Hyderabad, Andhra Pradesh 500007, India b Indian Institute of Science, Bangalore, India c Indian Immunologicals Limited, Hyderabad, India Received 16 November 2005; received in revised form 30 December 2005; accepted 2 January 2006 Available online 13 January 2006 Abstract The absence of standard guidelines from National and International regulatory agencies for the safety evaluation of biotechnology products challenges the ingenuity of toxicologists. At present, the development of standard pre-clinical toxicology protocols for such products is on an individual case basis. The present investigation is an attempt to evaluate the safety profile of the first indigenously developed DNA based anti-rabies vaccine in India. The test compounds were DNA rabies vaccine {DRV (100 g)} and combination rabies vaccine (CRV (100 g DRV and 1/50 dose of cell culture vaccine)), intended for clinical use by intramuscular route on 1, 7, 14 and 28 day. As per the regular mandatory requirements, the study has been designed to undertake acute (single dose—10 days), sub-chronic (repeat dose—28 days) and chronic (intended clinical dose—120 days) toxicity tests using three dose levels viz. therapeutic, average (2 × therapeutic dose) and highest dose (10 × therapeutic dose) exposure in Swiss Albino mice. The selection of the rodent model viz. Swiss Albino mice is based on affinity and rapid higher antibody response during the efficacy studies. Apart from physical, physiological, clinical, hematological and histopathology profiles of all target organs, the tier-I immunotoxicity parameters have also been monitored. There were no observational adverse effects even at levels of 10× therapeutic dose administration of DRV and CRV. The procedure also emphasizes on the designing of protocols for the products developed by recombinant technique. © 2006 Elsevier Ltd. All rights reserved. Keywords: Biotech products; Toxicology; DNA rabies vaccine (DRV); Combination rabies vaccine (CRV); Abhayrab; Safety evaluation; Pre-clinical toxicology 1. Introduction The safety evaluation of therapeutic agents at pre-clinical stage, especially of DNA/RNA based recombinant prod- ucts is gaining momentum even in the absence of stan- dard stipulated, regulatory guidelines [23]. In the recent past, many vaccines have been developed using modern biotechnological techniques, as they are not only potential preventive/therapeutic agents, but also economically viable ∗ Corresponding author. Tel.: +91 40 27008921; fax: +91 40 27019074. E-mail address: sesikerann@yahoo.com (B. Sesikeran). [11,12,18]. Among the vaccines available in India for vari- ous diseases, the one against rabies is produced from neural tissue (sheep brain) and is reported to be associated with autoimmune neuropathy [20]. Also, the anti-rabies vaccine developed by tissue culture technique is expensive and hence unaffordable to large populations in developing countries [10,17]. Based on earlier reports [24,25,1], a recombinant DNA rabies vaccine (DRV) has been developed indigenously for the first time in India by Indian Institute of Science s (IISc), Bangalore, India. The DRV was shown to induce rabies virus neutralizing antibodies in mice and monkeys and confer 0264-410X/$ – see front matter © 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.vaccine.2006.01.002