Generation of protective immune response against anthrax by oral immunization with protective antigen plant-based vaccine.

•We examine the feasibility of developing an oral plant-based vaccine against anthrax.•Protective antigen (PA) from Bacillus anthracis was expressed in tobacco and Indian mustard.•PA expressed in transgenic plants was found to be biologically active.•Immunization in mice indicated significant systemic and mucosal immune response.•The antibodies demonstrated lethal-toxin neutralization potential and conferred significant protection against toxin challenge.