RESUMO
Objective:To evaluate the impact of altered collagen Ⅱ(CⅡ) peptide(S268-270) on T cell activation.Methods:Altered CⅡ263-272 with G268,P269 and K270 consecutively substitution with A or G were synthesized using solid phase various concentrations were added to HLADR1 transfected APC.Expression of FITC stainning was analyzed by fluorescence-activated cell sorting,and the binding of altered CⅡ peptide to HLA-DR1 molecule on cell membrane was evaluated.Irridiated HLA-DR1 expressing APC was incubated with CⅡ263-272 or hemagglutinin(HA)306-318 and altered CⅡ peptides at various concentrations for 2 hours before T cells(3.19) were added.Supernatant was harvested and then added to IL-2 dependent CTLL cell.The cell proliferation was examined by methotetrazolium(MTT) method.Results:The altered CⅡ peptide and wild type of CⅡ263-272 were able to competitively bind to HLA-DR1 molecule expressed on cell membrane of transfected APC.CⅡ or HA induced T cell activation was significantly inhibited by the altered peptide S268-270.Conclusion:Altered CⅡ263-272 with G268,P269 and K270 consecutively substitutions with A or G inhibited CⅡ263-272 and HA306-318 induced T cell activation through competitively binding to HLA-DR1,suggesting a new approach in inhibition of T cell activation in RA.