Major Histocompatibility Complex Class I Peptide Presentation afterSalmonella entericaSerovar Typhimurium Infection Assessed via Stable Isotope Tagging of the B27-Presented Peptide Repertoire

Abstract

ABSTRACTReactive arthritis (ReA) induced by infection with several gram-negative bacteria is strongly associated with expression of the major histocompatibility complex class I molecule HLA-B27. It is thought that due to the intracellular lifestyle of ReA-inducing bacteria, bacterial fragments can be presented by HLA-B27. Cytotoxic T cells recognizing such bacterial peptides or other induced host peptides could cross-react with self peptides presented in the joints, giving rise to disease. Studies to analyze the B27 peptide repertoire in relation to infection were severely hampered, as complex peptide profiles obtained from separate infected and noninfected cell preparations had to be compared. For this study, we applied a new approach to examine the effect ofSalmonella entericaserovar Typhimurium infection on the B27 peptide repertoire presented by the HLA-B*2704 subtype associated with disease. Firstly, we showed that both host cell andS. entericaserovar Typhimurium proteins can be tagged metabolically with stable-isotope-labeled arginine. We then designed experiments so that either the tagged endogenous or tagged bacterial B*2704-presented peptide repertoires from infected cells could be analyzed by mass spectrometry from single peptide preparations that included uninfected controls. Using this new approach, we found no evidence for significant changes in endogenous B*2704 peptide presentation after infection or for anyS. entericaserovar Typhimurium-derived B27-bound peptide. In conclusion, the hypothesis thatS. entericaserovar Typhimurium induces changes in B27 peptide presentation could not be supported.