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.