Burkholderia pseudomallei capsular polysaccharide (CPS) (CPS)

Burkholderia pseudomallei capsular polysaccharide (CPS), specifically the Type I CPS, is a critical virulence factor and a primary surface antigen of the Gram-negative bacterium responsible for melioidosis [1, 8]. It consists of a linear homopolymer of -3)-2-O-acetyl-6-deoxy-beta-D-manno-heptopyranose-(1- residues and is essential for the pathogen's ability to evade the host immune system [3, 8]. CPS facilitates bacterial persistence in the blood by reducing the deposition of complement factor C3b and inhibiting opsonophagocytosis by host macrophages and neutrophils [8, 15]. Due to its high conservation across clinical isolates and its role in pathogenesis, CPS is a major target for the development of rapid diagnostics, such as the Active Melioidosis Detect (AMD) lateral flow assay [1, 14]. Therapeutic strategies under investigation include the use of CPS-specific monoclonal antibodies, such as mAb 4C4, for passive protection and the development of CPS-based glycoconjugate vaccines to induce protective IgG responses [5, 16]. While no human vaccine is currently licensed, CPS remains the most promising candidate for preventing the severe and often fatal manifestations of melioidosis [6, 16]. The structural integrity of the O-acetyl moiety is particularly important for antibody recognition and vaccine efficacy [1, 5]. Research into CPS is also vital for biodefense, as B. pseudomallei is classified as a Tier 1 select agent [16, 17].

Other names

CPS IType I CPSmanno-heptose capsular polysaccharideBurkholderia pseudomallei CPS

Monoclonal antibodies bind to the capsular polysaccharide to facilitate opsonophagocytosis and neutralize the pathogen, while glycoconjugate vaccines elicit protective IgG antibodies against the manno-heptose epitope [1, 6, 16].