Klebsiella pneumoniae surface antigens

Klebsiella pneumoniae surface antigens are a diverse group of molecules, including capsular polysaccharides (K-antigens), lipopolysaccharides (O-antigens), and outer membrane proteins, that are critical for the bacterium's survival and pathogenicity. The capsular polysaccharide (CPS) forms a thick protective layer that allows the pathogen to evade the host immune system by inhibiting phagocytosis and complement-mediated killing (1.1.2, 1.3.4). Lipopolysaccharides, specifically the O-antigen component, contribute to serum resistance and act as potent triggers for the host's innate immune response (1.2.3, 1.3.1). Additionally, surface structures like type I and type III fimbriae (e.g., MrkA) facilitate bacterial adhesion to host tissues and the formation of biofilms, which are essential for establishing persistent and antibiotic-resistant infections (1.2.1, 1.2.4). These antigens are primary targets for the development of vaccines and monoclonal antibodies, which aim to opsonize the bacteria or neutralize their virulence (1.3.3, 1.3.5). However, the extreme diversity of serotypes—with over 140 K-antigens identified—remains a significant challenge for achieving broad-spectrum therapeutic protection (1.3.5, 1.4.2).

Other names

K-antigenO-antigenCapsular polysaccharide (CPS)Lipopolysaccharide (LPS)Outer membrane proteins (OMPs)FimbriaePiliKlebsiella surface polysaccharides

Opsonization, Neutralization of virulence factors, Inhibition of bacterial adhesion, Complement activation, and Induction of protective humoral immunity.