Carrot cells expressing the VP1 and VP2 poliovirus proteins effectively elicited mucosal immunity

The WHO has recommended a combined schedule of vaccination including the oral (OPV) and the inactivated injectable vaccine. Each of these vaccines has advantages and limitations. Attenuated viruses in the OPV can revert into pathogenic forms, whereas the IPV generates limited intestinal mucosal immunity and its high cost restricts its application in developing countries. Besides, the cold chain required to maintain its stability also limits vaccine supply and transportation. Plant-based subunit vaccines are potential alternatives to circumvent such limitations. In the present study, carrot cell lines expressing VP1 and VP2 proteins were successfully generated. Mice were subcutaneously immunized and orally or subcutaneously boosted. Increased levels of both specific IgG and S-IgA were detected only in the feces of mice orally boosted. The cell lines obtained are safe, cheap, cold chain/poliovirus-free and a promising alternative to induce and maintain mucosal immunity favoring polio eradication. Key message Polio, oral vaccine, Carrot cells, Bioencapsulated antigen, Polio viral protein 1 (VP1), Polio viral protein 2 (VP2)