Vi antigen of Salmonella enetrica serovar Typhi — biosynthesis, regulation and its use as vaccine candidate

摘要: Vi capsular polysaccharide (Vi antigen) was first identified as the virulence antigen of Salmonella enterica serovar Typhi (S. Typhi), causative agent typhoid fever in humans. The presence differentiates S. from other serovars Salmonella. is a linear polymer consisting α-1,4-linked-N-acetyl-galactosaminuronate, whose expression controlled by three chromosomal loci, namely viaA, viaB and ompB. Both viaA region are present on Pathogenicity Island-7, large, mosaic, genetic island. encodes positive regulator locus composed 11 genes designated tviA-tviE (for biosyhthesis), vexA-vexE export) ORF 11. synthesized UDP-N-acetyl glucosamine series steps requiring TviB, TviC, TviE, regulation synthesis two regulatory systems, rscB-rscC (viaA locus) ompR-envZ (ompB locus), which respond to changes osmolarity. This highly immunogenic has been used for formulation one currently available vaccines against typhoid. Despite advancement area vaccinology, its pace progress needs be accelerated effective control programmes will needed proper disease management.