Oligopeptide-binding protein A is a potential target for combating Salmonella infection

Introduction Salmonella infection remains a pervasive diarrheal illness, particularly affecting populations in developing countries. The lack of an effective vaccine against non-typhoidal Salmonella is attributable to antigenic diversity among serotypes, incomplete understanding of protective immune mechanisms, and the difficulty in identifying conserved antigens capable of eliciting broad cross-protective immunity. Methods To identify conserved Salmonella antigens, we established a Salmonella -specific monoclonal antibody library using heat-killed bacteria. Candidate antigens recognized by monoclonal antibodies were characterized, and their functional relevance was evaluated through analyses of bacterial growth, respiratory activity, and protective effects in a murine Salmonella infection model. Results We identified L2-1H11, a monoclonal antibody that recognizes OppA, a conserved antigen present across multiple Salmonella serotypes. L2-1H11 was associated with suppression of bacterial growth and respiratory activity and attenuated enteritis pathology in Salmonella -infected mice. Conclusion These findings identify OppA as a conserved Salmonella antigen and suggest that it may represent a promising target for the development of subcutaneous and oral vaccines against Salmonella .