Cecal Tonsil Transcriptome Response to Salmonella Enteritidis Contribute to Colonization Persistence in Young Chicks

Long-term survival and the persistence of the bacteria in the host suggest either host unresponsiveness or induction of immunological tolerant response towards the pathogen. The role of host immunological response to persistent colonization of Salmonella Enteritidis (SE) in chicken remain poorly understood. In current study, we performed a cecal tonsil transcriptome analysis in 2 weeks old SE persistent infection model to accurately examine the dynamic host immunological responses in the gastrointestinal tract. RNA-sequencing analysis revealed an overall host tolerogenic adaptive immune regulation occurrence in major gut-associated lymphoid tissue, cecal tonsil, during SE infection. Consistent down-regulation of the annotated gene, metallothionein 4 at all four post-infection timepoints suggested the pathogen-associated manipulation of the host zinc regulation in addition to possible immune modulatory effect. Delayed activation in B cells receptor signaling pathway and failure to sustain its continue activation status during infection was further supported by insignificant amount of circulatory antibody production. Ineffective B cells response towards pathogen could played a role in weakening antigen uptake and subsequent B cells induction to trigger appropriate T cells response. Up-regulation in key negative regulator of T cell proliferation, TOB further highlighted the lack of T cells involvement as well as overall host tolerogenic immune response that promote persistent colonization of SE in young layer chicks.