title: Improved delivery of the OVA-CD4 peptide to T helper cells by polymeric surface display on Salmonella.
abstract: BACKGROUND
  Autotransporter proteins represent a treasure trove for molecular engineers who modify Gram-negative bacteria for the export or secretion of foreign proteins across two membrane barriers. A particularly promising direction is the development of autotransporters as antigen display or secretion systems. Immunologists have been using ovalbumin as a reporter antigen for years and have developed sophisticated tools to detect specific T cells that respond to ovalbumin. Although ovalbumin-expressing bacteria are being used to trace T cell responses to colonizing or invading pathogens, current constructs for ovalbumin presentation have not been optimized.
  
  
  RESULTS
  The activation of T helper cells in response to ovalbumin was improved by displaying the OVA-CD4 reporter epitope as a multimer on the surface of Salmonella and fused to the autotransporter MisL. Expression was optimized by including tandem in vivo promoters and two post-segregational killing systems for plasmid stabilization.
  
  
  CONCLUSIONS
  The use of an autotransporter protein to present relevant epitope repeats on the surface of bacteria, combined with additional techniques favoring stable and efficient in vivo transcription, optimizes antigen presentation to T cells. The technique of multimeric epitope surface display should also benefit the development of new Salmonella or other enterobacterial vaccines.
authors.forename: Junjie
authors.initials: J
authors.lastname: Zhang
authors.forename: Leon
authors.initials: L
authors.lastname: De Masi
authors.forename: Beena
authors.initials: B
authors.lastname: John
authors.forename: Wenxin
authors.initials: W
authors.lastname: Chen
authors.affiliation: Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania 19104, USA. dmschiff@vet.upenn.edu.
authors.forename: Dieter M
authors.initials: DM
authors.lastname: Schifferli
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D015704:CD4 Antigens / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002473:Cell Wall / Q000378:metabolism; D000939:Epitopes / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D010047:Ovalbumin / Q000235:genetics* / Q000378:metabolism*; D010455:Peptides / Q000235:genetics / Q000378:metabolism*; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics; D012475:Salmonella / Q000378:metabolism*; D006377:T-Lymphocytes, Helper-Inducer / Q000166:cytology / Q000276:immunology / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D015704:CD4 Antigens; D000939:Epitopes; D026901:Membrane Transport Proteins; C460865:MisL protein, Salmonella enterica; D010455:Peptides; D011993:Recombinant Fusion Proteins; D010047:Ovalbumin