Mucosal immunisation and vaccines

The immunisation of mucosal surfaces in mammals is vitally important to the survival of any given species. A large number of pathogenic microorganisms are first encountered at the mucosal surface. It is this first contact that may lead to the invasion and colonisation by a pathogen and the subsequent onset of disease. The gastrointestinal mucosa has a very large surface area, approximately 250 m2in the adult human (1), which can be used by microorganisms for invasion. This interaction between the microorganisms and host mucosal cells allows the scientist and the clinician an excellent field of battle for immunological priming and therefore vaccination against the invading pathogens. This approach has great potential in barring the entry to a range of bacterial, viral or protozoan pathogens before colonisation and the onset of disease. The prevention of such infections is very important both on a social and an economic scale. Rapid and relentless transmission is all too common when an infection can establish a base within the community. Fortunately, these outbreaks are decreasing in frequency in the developed world, however, in periods of human crisis or natural disaster the spectre raises its head. This has been evident in recent years with cholera outbreaks. In 1994, 45,000 people died and an estimated 600,000 were infected as a result ofVibrio cholerae01 outbreak in Rwandan refugee camps in just a three week period (2). Additionally, the need for a clean and rapid method of dispensation is also required, which is where the case for orally delivered vaccines also needs to be addressed.