Streptococcus uberis surface and cell-wall antigens

Streptococcus uberis surface and cell-wall antigens are a diverse group of proteins and polysaccharides located on the exterior of the S. uberis bacterium, which is a leading cause of bovine mastitis worldwide. These antigens, such as the Streptococcus uberis adhesion molecule (SUAM) and the plasminogen activator (PauA), are critical for the pathogen's ability to adhere to, invade, and colonize the mammary gland (Almeida et al., 2011; Rosey et al., 1999). SUAM specifically facilitates binding to host lactoferrin, while PauA activates host plasminogen to promote tissue invasion and bacterial spread. These surface-exposed molecules serve as the primary targets for vaccine development, most notably the commercial UBAC vaccine, which utilizes cell-wall components to stimulate a protective immune response (Collado et al., 2018). By inducing the production of specific antibodies, these therapies aim to block bacterial attachment and enhance clearance by host immune cells through opsonophagocytosis. Despite their potential, the significant antigenic variation among different S. uberis strains remains a challenge for the development of a universally effective vaccine. Understanding the molecular structure of these antigens is essential for improving the efficacy of preventative treatments in the dairy industry.

Other names

Streptococcus uberis surface proteinsS. uberis cell wall proteinsBovine mastitis antigensStreptococcus uberis adhesion molecule (SUAM)Plasminogen activator uberis (PauA)GapC proteinOligopeptide-binding protein (OppA)

Vaccines targeting these antigens induce the production of specific antibodies (e.g., IgG1 and IgG2) that block bacterial adherence to mammary epithelial cells and neutralize virulence factors like PauA, thereby preventing the establishment of intramammary infection (Almeida et al., 2011; Collado et al., 2018).