Immunization with Hap adhesin found protective in murine study.

2002 DEC 11 - (NewsRx.com & NewsRx.net) -- Washington University researchers suggest intranasal immunization with the protein Hap adhesin formulated with mutant cholera toxin may help prevent nontypeable Haemophilus influenzae disease.

"Nontypeable Haemophilus influenza e is a common cause of respiratory tract disease and initiates infection by colonizing the nasopharynx. The H. influenzae Hap adhesin is an autotransporter protein that was discovered because it promotes intimate interaction with human epithelial cells. Hap contains an extracellular domain called Hap(s) that has adhesive and protease activity and an outer membrane domain called Hap(beta) that serves to present Hap(s) on the surface of the cell," explained D. Cutter and colleagues.

They immunized BALB/c mice intranasally with Hap(s) purified from nontypeable H. influenzae strain P860295.

"Immunization stimulated significant mucosal and serum anti-Hap(s) antibody titers, which were augmented by the addition of mutant cholera toxin (CT-E29H) as an adjuvant," Cutter's team said.

They reported that "[i]mmunization was associated with a marked reduction in the density of nasopharyngeal colonization when mice were challenged ...