Bacterial ghosts as carrier and targeting systems for mucosal antigen delivery

Abstract

The application of new strategies to develop effective vaccines is essential in modern medicine. The bacterial ghost system is a novel vaccine delivery system endowed with intrinsic adjuvant properties. Bacterial ghosts are nonliving Gram-negative bacterial cell envelopes devoid of cytoplasmic contents while maintaining their cellular morphology and native surface antigenic structures including bioadhesive properties. They are produced by PhiX174 protein E-mediated lysis of Gram-negative bacteria. The intrinsic adjuvant properties of bacterial ghost preparations enhance immune responses against envelope-bound antigens, including T-cell activation and mucosal immunity. Since native and foreign antigens can be expressed in the envelope complex of ghosts before E-mediated lysis, multiple antigens of various origin can be presented to the immune system simultaneously. In addition, the extended bacterial ghost system represents a platform technology for specific targeting of DNA-encoded antigens to primary antigen-presenting cells. The potency, safety and relatively low production cost of bacterial ghosts offer a significant technical advantage, especially when used as combination vaccines.