Abstract for presentation at Australia and New Zealand Society of Nephrology Annual Scientific Conference

IFN-gamma-Treated Renal Tubular Cells Express Class II MHC Molecules But Do Not Induce Proliferation In Allogeneic CD4+ T Cells

  • Ms Tania Polhill, Centre for Kidney Research, Children's Hospital at Westmead and University of Sydney at Royal North Shore Hospital, Australia
  • Dr Yuan Min Wang, Centre for Kidney Research, Children's Hospital at Westmead, Australia
  • Dr Geoff Zhang, Centre for Kidney Research, Children's Hospital at Westmead, Australia
  • Prof Carol Pollock, University of Sydney at Royal North Shore Hospital, Australia
  • Prof David Harris, Centre for Transplant and Renal Research, University of Sydney at Westmead Hospital, Australia
  • Dr Xin-Ming Chen, University of Sydney at Royal North Shore Hospital, Australia
  • Stephen Alexander, Centre for Kidney Research, Children's Hospital at Westmead, Australia

    • Background: Proximal Tubular Cells (PTCs) are capable of expression of MHC Class II molecules after exposure to interferon-gamma. Other costimulatory molecules expressed include the inhibitory molecule PD-L1. It is unclear whether active engagement of alloreactive CD 4+ T cells can occur in an allograft by non-classical antigen presenting cells such as PTCs. Aim: To evaluate the capacity of PTCs to induce alloproliferation and alter regulatory cell composition.
    Methods: Human PTCs were cultured to confluence and then treated with IFN-gamma (100ng/ml). MHC Class II expression was assessed by flow cytometry. Peripheral Blood Mononuclear Cells stained with CFSE and cocultured with IFN-gamma-pretreated PTCs or irradiated allogeneic PBMCs (control stimulators). Proliferation was assessed by reduction in CFSE fluorescence in CD4 positive cells at Day 3 (D3) and the regulatory subset assessed by intracellular staining for FOXP3.
    Results: PTCs expressed increasing amounts of Class II after IFN-gamma treatment: Class II D0 (0%); D1 (17%); D2 (76%); D3 (81%); D4 (98%). CD4 T cells showed no proliferation (0.9%) when cultured alone, and 12% proliferation upon coculture with allogeneic stimulators. However by D4 CD4 T cells did not proliferate (<1%) when cocultured with either Class II-expressing or non-Class II-expressing PTCs. FOXP3 expression reached 9.1% in CD4 T cells, and 9.6% upon coculture with Class II expressing PTCs.
    Summary: PTCs express Class II molecules after IFN-gamma treatment. However this does not induce allogeneic proliferation or alteration in regulatory CD4 T cell numbers. This may be due to failure of costimulation or expression of inhibitory molecules by PTCs.

    Conference Organiser - ICMS Pty Ltd