Induction of protective immunity against microbial challenge by targeting antigens expressed by probiotic bacteria to mucosal dendritic cells

Efficient vaccines combined with adjuvants potentiate and enhance antibody avidity and increase T cell longevity, particularly in individuals with compromised immunity. The efficacy of a novel vaccine can be improved by specifically targeting its immunogenic subunits and expressing it in live probiotic vector (i.e. Lactobacillus acidophilus) that protects vaccine bioavailability and to induces not only mucosal but also systemic immunity against microbes. Accordingly, our data clearly show that specific Lactobacillus species (L. gasseri) not only optimally activate DCs but also deliver targeted antigens to mucosal DCs via 12-mer peptides derived from a phage display library resulting in robust humoral and T cell immunity against microbial challenge. This effort is accomplished via novel tools that provide "targeting" of the vaccine, evaluation of innovative vaccine effectiveness against a wide array of microbes, and controlling gene expression/presentation technologies in probiotic lactobacilli that can be orally consumed at high levels resulting in natural delivery of a "targeted" antigen to mucosal DCs. In this review I will discuss the potential benefits and efficacy of the employed vaccine strategy that may be feasible for various studies in the field.