Replication Kinetics of <I>Salmonella</I> Enteritidis Live Vaccine in the Immune Organs of Chicken after Subcutaneous Immunization

Abstract

We used a real-time PCR for Salmonella Enteritidis to detect the genomic DNA of Salmonella Enteritidis live vaccine in the immune organs, including the bursa of Fabricius, thymus, spleen, and Harderian gland, from chicken after subcutaneously vaccinated at different time points. Significant numbers of Salmonella Enteritidis genomes in the immune organs were first detected at 12 hour (post-vaccination) p.v., and subsequently rose to peak levels during 48 h to 72 h p.v. The rapid early increase of vaccine levels in all samples examined followed by a steady decline from 84 h to 15 days p.v. The real-time PCR analysis of a variety of tissues is significant for further investigation of the mechanism of vaccinal protection, and the optimization of vaccination regimes.