Abstract
Vaccination of chinchillas with nontypeable Haemophilus influenzae (NTHi) lipooligosaccharide (LOS) conjugates protected against otitis media. Correlations between the levels of conjugate-induced LOS antibodies (Abs) in sera and middle ear fluids (MEFs) and Ab-mediated biological functions and protection were examined. Following parenteral vaccination and middle ear challenge, all vaccinated animals, but none of the controls, had high titers of anti-LOS in their sera and MEFs. There was a correlation between the levels of anti-LOS IgG+M, IgG or IgA in the sera and in the MEFs ( P<0.001). An inverse correlation was found between the level of serum IgG+M and bacterial counts and between the levels of MEF Abs and bacterial counts at the early postchallenge stage ( P<0.05). Of the 39 vaccinated animals, 44% showed complete protection against otitis media, 46% (18/39) of their sera inhibited adherence of NTHi to human epithelial cells, 49% (19/39) demonstrated bactericidal activity and 49% (19/39) showed opsonophagocytic activity. In contrast, none of the controls (19) were protected, none of their sera inhibited bacterial adherence or had bactericidal activity and only 21% showed opsonophagocytosis. Our interpretation is that vaccine-induced LOS Abs transuded into the middle ear and conferred immunity to NTHi by binding to LOS of NTHi, inhibition of NTHi adherence to epithelial cells and complement-mediated bacteriolysis (or opsonophagocytosis).
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call