title: Identification of epitopes recognised by mucosal CD4(+) T-cell populations from cattle experimentally colonised with Escherichia coli O157:H7.
abstract: Vaccines targeting enterohaemorrhagic Escherichia coli (EHEC) O157:H7 shedding in cattle are only partially protective. The correlates of protection of these vaccines are unknown, but it is probable that they reduce bacterial adherence at the mucosal surface via the induction of blocking antibodies. Recent studies have indicated a role for cellular immunity in cattle during colonisation, providing an impetus to understand the bacterial epitopes recognised during this response. This study mapped the epitopes of 16 EHEC O157:H7 proteins recognised by rectal lymph node CD4(+) T-cells from calves colonised with Shiga toxin producing EHEC O157:H7 strains. 20 CD4(+) T-cell epitopes specific to E. coli from 7 of the proteins were identified. The highly conserved N-terminal region of Intimin, including the signal peptide, was consistently recognised by mucosal CD4(+) T-cell populations from multiple animals of different major histocompatibility complex class II haplotypes. These T-cell epitopes are missing from many Intimin constructs used in published vaccine trials, but are relatively conserved across a range of EHEC serotypes, offering the potential to develop cross protective vaccines. Antibodies recognising H7 flagellin have been consistently identified in colonised calves; however CD4(+) T-cell epitopes from H7 flagellin were not identified in this study, suggesting that H7 flagellin may act as a T-cell independent antigen. This is the first time that the epitopes recognised by CD4(+) T-cells following colonisation with an attaching and effacing pathogen have been characterised in any species. The findings have implications for the design of antigens used in the next generation of EHEC O157:H7 vaccines.
authors: Farm Animal Practice, Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK.|Division of Immunity and Infection, The Roslin Institute, The University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK.
authors: Alexander
authors: A
authors: Corbishley
authors: Division of Immunity and Infection, The Roslin Institute, The University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK.
authors: Timothy K
authors: TK
authors: Connelley
authors: Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, UK.
authors: Eliza B
authors: EB
authors: Wolfson
authors: Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, EH26 0PZ, UK.
authors: Keith
authors: K
authors: Ballingall
authors: Division of Immunity and Infection, The Roslin Institute, The University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK.|Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, EH26 0PZ, UK.
authors: Amy E
authors: AE
authors: Beckett
authors: Division of Immunity and Infection, The Roslin Institute, The University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK.
authors: David L
authors: DL
authors: Gally
authors: Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, EH26 0PZ, UK. tom.mcneilly@moredun.ac.uk.
authors: Tom N
authors: TN
authors: McNeilly
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000502:physiology; D002417:Cattle; D002418:Cattle Diseases / Q000276:immunology*; D002460:Cell Line; D000939:Epitopes / Q000276:immunology*; D004927:Escherichia coli Infections / Q000276:immunology / Q000662:veterinary*; D019453:Escherichia coli O157 / Q000276:immunology*; D005434:Flow Cytometry / Q000662:veterinary; D007413:Intestinal Mucosa / Q000276:immunology / Q000382:microbiology; D008856:Microscopy, Fluorescence / Q000662:veterinary
chemical_list: D000939:Epitopes