Attachment of the outer membrane lipoprotein (OprI) of Pseudomonas aeruginosa to the mucosal surfaces of the respiratory and digestive tract of chickens.

The development of mucosal vaccines requires antigen delivery and adjuvant systems that can efficiently help in presenting vaccine antigens to the mucosal immune system. The outer membrane lipoprotein I (OprI) of Pseudomonas aeruginosa seems to possess both the quality to induce a non-specific immune response (adjuvant effect through its lipid tail) as well as the quality to facilitate uptake of the vaccine antigen by interacting with Toll-like receptor 2/4 (TLR2/4) on antigen-presenting cells (APC) and epithelial cells (adhesion effect). Here, we show for the first time the adhesion of OprI to epithelial cells of the trachea and small intestine of chickens. Adhesion could be seen on cryosections after in vitro as well as after in vivo incubation of the trachea and intestine. This proves the value of OprI as a fusion partner in mucosal protein vaccine development, which is especially important for poultry where mass vaccination is only possible by the respiratory or oral route.