POLYSACCHARIDE-IRON-REGULATED CELL-SURFACE PROTEIN CONJUGATE VACCINE - ITS ROLE IN PROTECTION AGAINST KLEBSIELLA PNEUMONIAE-INDUCED LOBAR PNEUMONIA

Klebsiella pneumoniae has become an important cause of both community- acquired and nosocomial infections. In this study an attempt was made to study the immunogenicity of iron-regulated cell surface proteins (I RCSP) alone or in conjunction with the polysaccharide moiety of lipopo lysaccharide (LPS) of K. pneumoniae. The polysaccharide-iron-regulated cell surface protein conjugate (PS-IRCSP) was non-toxic and non-pyrog enic. It was found to be immunogenic and the protection afforded by th e conjugate against the challenge strain was observed in a rat lobar p neumonia model. The protection observed with the conjugate was higher than that observed with polysaccharide or IRCSP alone. The conjugate e licited both agglutinating and bactericidal antibodies. Enhanced phago cytosis was observed for the alveolar macrophages obtained from the lu ngs of animals treated with conjugate compared with macrophages obtain ed from animals treated with other antigenic preparations.