Das Projekt "Entwicklung eines Pflanzen-basierten Impfstoffs gegen Gebärmutterhalskrebs: Expression des humanen Papilloma Virus L1 Antigens, lokalisiert im Plastom" wird vom Umweltbundesamt gefördert und von Universität für Bodenkultur Wien, Institut für Pflanzenbau und Pflanzenzüchtung durchgeführt. The production of vaccines in plants bears a frequently discussed risk factor: The containment of potentially bio-hazardous genes. Transgenes transformed to the nucleus can escape to the environment through pollen flow. We can limit the risk of pollen-mediated transgene dissemination in the first line by use of the chloroplast transformation method. The advantages of plastid transformation consist in the precision of the transgene insertion via homologous recombination, in their maternal inheritance, the high transformation predictability, and circumvention of epigenetic effects, as are silencing and methylation. By this approach we determine the potential to synthesize antigen L1 of the Human Papilloma Virus (HPV) for vaccination in tobacco plastids. Vaccines can be delivered as antigens either for peripheral or oral immunization. Transformation of plants with genes carrying selected antigens of the respective pathogen allows producing immunogenic proteins on the field with very high yields. Our goal is the production of an antigen vaccine against Human Papilloma Virus (HPV), which causes cervical cancer prestages in nearly 2 Prozent of all women in Germany. In order to synthesize the antigenic L1 epitope from HPV 16 a chloroplast transformation vector will be constructed, which will contain a synthetic expression cassette: For increased transcription: two different promoters, for enhanced translation it will carry a 5 motif from the T7 phage G10L sequence. Further the L1 gene will be N-terminally fused to the sequence codons of the first 14 amino acids of GFP (green fluorescent protein) which confers an increased translation. On transcriptional level this construct is followed by a selection cassette containing the aadA gene. Regenerating calli carrying these constructs will be selected on a medium containing spectinomycin. Positive transformants will be identified by PCR and Southern analysis. Further Western blot analysis will prove successful expression of the L1 protein. The novel transformants are then tested on correct folding of the LTB-L1 fusion protein: The recombinant protein can be identified with conformation specific antibodies which only bind when L1 proteins formed virus like capsomers. Our further work is aimed to set up an inducible antigen expression system, which is regulated through chemical induction By this work, plant transformants will be shown to be a reasonable alternative for production of vaccines. Due to these results the next step to proof the immunogenicity has the best prospects.