S.Typhi H

Salmonella Typhi is a pathogenic bacterium responsible for causing typhoid fever, a serious illness affecting millions of people worldwide. One of the key components of this bacterium is the H antigen, a flagellar protein that plays a crucial role in its motility and virulence.

The H antigen is part of the Kauffmann–White classification system, which categorizes Salmonella species based on their surface antigens . The H antigen is specifically associated with the flagellar proteins, which are essential for the bacterium’s motility. The recombinant form of this antigen is produced using Escherichia coli (E. coli), resulting in a full-length flagellin sequence of 301 amino acids, fused to a 6 His Tag at the C-terminus .

The H antigen is a significant factor in the pathogenicity of Salmonella Typhi. It enables the bacterium to move and invade host tissues, contributing to its ability to cause infection. The recombinant form of this antigen is used in various research and diagnostic applications due to its high sensitivity, specificity, and reproducibility .

The H antigen facilitates the motility of Salmonella Typhi by forming part of the flagellum, a whip-like structure that propels the bacterium. This motility is crucial for the bacterium to navigate through the host’s intestinal environment and establish infection.

The expression of the H antigen is tightly regulated within the bacterium. Salmonella Typhi can exhibit phase variation, switching between different motile phenotypes. This ability to alter its surface antigens helps the bacterium evade the host’s immune system .

Recombinant Salmonella Typhi H antigen is widely used in immunization protocols to generate antibodies that specifically target this protein. These antibodies are valuable tools in the study of typhoid fever and the development of diagnostic tests and vaccines .