Detection of Multi-Serotype Salmonella Based on Conserved Antigen Molecular Recognition

Salmonella is a common foodborne pathogen. Antibodies against Salmonella are typically generated using inactivated whole bacterial cells as immunogens; however, the lack of studies on the recognition mechanism has limited antibody development. In this work, immunoinformatics-based simulation was employed to screen outer membrane proteins with high immunogenicity as antigens, successfully generated high-affinity monoclonal antibodies. The selected antibody pair 19F6-4E7 was capable of detecting 12 Salmonella serovars. A gold immunochromatographic strip (GICS) was established with visual LOD values of 4.0 × 103-4.0 × 104 CFU/mL in milk and 4.0 × 103-2.5 × 105 CFU/mL in chicken. It also correctly identified positive clinical fecal samples, enabling point-of-care testing. The high affinity of the antibody is attributed to hydrogen bonds and salt bridge interactions between the CDR region and the antigen. This study provides a molecular structural basis for further antigen design and the rational engineering of antibodies.