Intranasal Immunization Protects Mice From H. influenzae Ear Infection.(Brief Article)

2001 MAY 9 - (NewsRx.com & NewsRx.net) --

by N.R. Saltmarsh, staff medical writer - Mice immunized with an outer membrane protein of non-typeable Haemophilus influenzae (NTHi) are better able to fight tympanic infection with the bacterial infection and subsequent middle ear effusions (MEEs) than control mice, report researchers working in Japan.

Albert Sabirov and colleagues at Oita Medical University noted that NTHi is a major pathogen causing otitis media (OM) and proposed that vaccination with P6, one of its outer membrane proteins and a common antigen to all strains, could protect against ear infection.

Their previous work had shown that intranasal immunization with P6 and cholera toxin (CT) could induce P6-specific immunoglobulin A (IgA) antibodies in the middle ear.

"In the present study, we assessed the effect of intranasal immunization for the protection against NTHi-induced OM," reported Sabirov et al.

They immunized mice intranasally with P6/CT on days 0, 7, and 14, while control mice were given phosphate-buffered saline without antigen. One week later, they infected mice with live NTHi (10(7) colony-forming units [CFU]) by injection into the tympanic cavity to induce OM.

Three and seven days after bacterial challenge, the researchers measured MEEs. The immunized mice showed enhanced clearance of NTHi from the middle ear compared to control mice.