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

Abstract 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.