Transgenic carrot tap roots expressing an immunogenic F1-V fusion protein from Yersinia pestis are immunogenic in mice

Expression of the protective F1 and V antigens of Yersinia pestis, as a fusion protein, in carrot was pursued in an effort to develop an alternative vaccine production system against the serious plague disease. Transgenic carrot plants carrying the F1-V encoding gene were developed via Agrobacterium-mediated transformation. Presence, integration, and expression of the F1-V encoding gene were confirmed by polymerase chain reaction (PCR), DNA gel blot analysis, and reverse-transcriptase (RT)-PCR analyses, respectively. An ELISA assay confirmed the antigenicity of the plant-derived F1-V fusion protein. Immunogenicity was evaluated subcutaneously in mice using a soluble protein extract of freeze-dried transgenic carrot. Significant antibody levels were detected following immunization. These results demonstrated that the F1-V protein could be expressed in carrot tap roots, and that the carrot F1-V recombinant protein retained its antigenicity and immunogenicity.