Gene Therapy (2018) 25:485–496 https://doi.org/10.1038/s41434-018-0033-8 ARTICLE In vivo delivery of pPERDBY to BALB/c mice by LacVax ® DNA-I and comparison of elicited immune response with conventional immunization methods Bhrugu Yagnik 1,2 ● Drashya Sharma 1,2 ● Harish Padh 3 ● Priti Desai 1,4 Received: 10 February 2018 / Revised: 29 May 2018 / Accepted: 30 May 2018 / Published online: 14 August 2018 © Springer Nature Limited 2018 Abstract The non-invasive food grade Lactococcus lactis (L. lactis) represents a safe and attractive alternative to invasive pathogens for the delivery of plasmid DNA at mucosal sites. We have earlier shown the DNA delivery potential of r-L. lactis harboring DNA vaccine reporter plasmid; pPERDBY in vitro. In the present work, we examined in vivo delivery potential of food grade non-invasive r-L. lactis::pPERDBY (LacVax ® DNA-I) in BALB/c mice. Moreover, using EGFP as a model antigen, we also characterized and compared the immune response elicited by LacVax ® DNA-I with other conventional vaccination approaches using protein and naked DNA immunization. The presence of antigen-specific serum IgG and fecal secretory IgA (sIgA) antibodies demonstrated in vivo DNA delivery and immune elicitation potential of the developed LacVax ® DNA-I. As compared with intramuscular injection, oral delivery of pPERDBY via L. lactis resulted in a significantly rapid increase in IgG and higher sIgA titers, indicating the immunogenic and immunostimulatory properties of the LacVax ® DNA-I. The needle-free immunization with LacVax ® DNA-I led to increased production of IL-4, an indicator of Th2 screwed response. To the best of our knowledge, this report for the first time outlines comparison of orally administered LacVax ® DNA-I with other conventional vaccination approaches. Introduction Vaccination is one of the most effective ways to prevent infection and disease establishment. Different strategies for vaccine development have been deployed against a wide range of pathogens [1]. Mucosal immunization with plas- mid DNA has been studied with great interest in generating antigen-specific systemic as well as mucosal immunity [2]. Different bacterial carriers have been used for the delivery of DNA vaccines to mucosal sites. In the earlier attempts, attenuated invasive pathogens such as Salmonella, Shigella, Yersinia, and Listeria were used as a vaccine carrier [3]. The adhesive and invasive properties of these bacteria allow efficient DNA delivery to professional and non-professional phagocytes, leading to enhanced expression and presentation of antigen [4]. However, the major risk of reversion to virulent phenotype and associated safety issues discourage the use of attenuated invasive pathogens [3]. The use of food grade Lactococcus lactis (L. lactis) as a DNA delivery vehicle represents an attractive alternative to attenuated pathogens [3]. The GRAS (generally regar- ded as safe) status of L. lactis has paved the way for its application in oral delivery of antigens and numerous therapeutic molecules [5]. With this background, our group has explored L. lactis for the development of a mucosal vaccine against Shigella. We have reported effi- cient expression and delivery of outer membrane protein A (OmpA) of Shigella dysenteriae type-1 (SD-1) in L. lactis and evaluated its immunogenic potential in BALB/c mice [5, 6]. * Priti Desai preetindesai79@gmail.com preetindesai@yahoo.co.in 1 Department of Cell and Molecular Biology, B. V. Patel Pharmaceutical Education and Research Development (PERD) Centre, Ahmedabad, Gujarat, India 2 B. R. D. School of Biosciences, Sardar Patel University, Vallabh Vidhyanagar, Gujarat, India 3 Sardar Patel University, Vallabh Vidhyanagar, Gujarat, India 4 School of Biological Sciences & Biotechnology, Institute of Advanced Research, Koba, Gandhinagar, Gujarat, India 1234567890();,: 1234567890();,: