Lectin-mediated mucosal delivery of drugs and microparticles.

Absorption of drugs and vaccines at mucosal surfaces may be enhanced by conjugation to appropriate bioadhesins which bind to mucosal epithelia. Bioadhesins might also permit cell- and site-selective targeting. One approach is to exploit surface carbohydrates on mucosal epithelial cells for lectin-mediated delivery. We review work supporting the use of lectins as mucosal bioadhesins in the gastrointestinal and respiratory tracts, the oral cavity and the eye. The gastrointestinal tract is particularly favoured for mucosal delivery. Many studies have demonstrated that the antigen sampling intestinal M cells offer a portal for absorption of colloidal delivery vehicles. Evidence is presented that M cell targeting may be achieved using M cell-specific lectins, microbial adhesins or immunoglobulins. While many hurdles must be overcome before mucosal bioadhesins can guarantee consistent, safe, effective mucosal delivery, this is an exciting area of research that has important implications for future drug and vaccine formulation.