Management of pulmonary infection : experimental studies on oral immunization and surfactant replacement therapy

This thesis aims at evaluating two "new" concepts for the management of pneumonia. The first concept, oral immunization, seems a promising approach towards prevention of pneumonia. Extensive programs have been developed for active immunoprophylaxis to immunize against specific microbial pathogens, and vaccines introduced into clinical practice since the 1970s include those against H. influenzae, meningococs, pneumococs, pseudomonas, hepatitis B virus and rabies. However, controversies surrounding established vaccines and the search for vaccines against other pathogens constantly stimulate investigations on the development of new vaccines. Therefore, and because oral administration of vaccines is convenient, much attention has been paid to the development of vaccines for oral administration. It is proven that oral administration of vaccine of viral or bacterial origin can induce a mucosal immune response, but the possibility of oral immunization with bacterial lysate for the prevention of viral pneumonia has not been well documented. The first part of this thesis presents investigations on oral immunization with a new polyvalent bacterial lysate against both bacterial and viral pathogens that may cause pneumonia. The second concept, surfactant replacement therapy, has already proven its value in the prevention and treatment of idiopathic respiratory distress syndrome (IRDS) of the newborn, which is caused by a surfactant deficient state of the premature lungs. Several studies on the origin and nature of the adult respiratory distress syndrome (ARDS) have demonstrated a surfactant deficient state of the lungs of ARDS-patients and frrst clinical trials of surfactant replacement in ARDS patients have proven the beneficial effects of surfactant replacement. Pneumonia may lead to a clinical syndrome closely resembling ARDS. Therefore, the second part of this thesis presents investigations on surfactant replacement therapy during ARDS-like viral pneumonia