Because this approach had not been tried before, we needed to demonstrate that our ideas were feasible. After two years, even sceptics were forced to admit that a number of LAB could be used as vaccine vectors. The result created ripples of excitement. Since LAB can be taken by mouth, they would be much easier to administer than injected preparations. Having established protocols to ensure the reproducibility of their results, the partners investigated whether mucosal immunity could be induced in animals by administering a live LAB vaccine through different immunisation routes.
Most pathogenic organisms get into the body through the mucosal surface.
The network engineered LAB to carry two different molecules. One is a component of the toxin produced by the bacterium that causes tetanus, the other a protein from the Aujeszky's disease virus, which causes pseudorabies in pigs. Using these test antigens, the partners tested several strains of LAB and showed that they could induce a good antibody response to the antigen they carried. Moreover, results to date show that the immune response protects against challenge with live organisms in the tetanus model. Preliminary experiments have also been conducted with Streptococcus gordonii in monkeys.