Development of DNA vaccine(s) against Mycobacterium specific genes and prime boost with BCG

Abstract

Tuberculosis (TB), the white plague of Europe is still uncontrolled and fatal in many parts of the world including Pakistan. It is a major cause of morbidity and mortality in human and domestic animals in Pakistan. No new vaccine in the last hundred years has been developed except for a few encouraging results from recombinant and DNA vaccines in the past two decades. Five Mycobacterium specific genes (Rv0379, Rv3914, Rv3006, Rv0432+SP, and Rv0432-SP) were selected to develop DNA vaccine(s). All the constructs were tested on mice using both naked DNA and prime-boost methodologies. Forty-five BALB/c mice were divided into three main groups; DNA vaccine group, BCG Prime boost group, and Control group. Post-vaccine (PV) and post-challenge (PC) immune responses were confirmed through cytokine ELISA and qRT PCR. IFN-γ was additionally checked in plasma as well. Based on cytokine ELISA PC immune responses showed significant differences in TNF-α levels for both naked DNA vaccine groups (Rv0379, Rv3006, and Rv0432-SP) and BCG primed Rv3914 group in comparison to the BCG control group (p<0.05). Based on qRT PCR, IL-6, TNF-α, IFN-γ, and IL-1β showed no significant difference among all the vaccines and BCG control groups (CT range 25- 30). IFN-γ levels in plasma were analyzed PC; two vaccines Rv3006/LppZ and BCG primed Rv0432/SodC-SP (highest mean value 1360.35 pg/ml) have shown significant results (cutoff value 21pg/ml) at 63 days. All the vaccine construct(s) alone or in combination have significant therapeutic effects in comparison to BCG and negative control groups.