Figure 4

HLA-B27/Chlamydia peptide tetramer-binding synovial T cells in patient nos 2 and 3. In patient no. 3, 0.09% Chlamydia peptide 195-specific and 0.06% peptide 68-specific CD8⁺ T cells were identified. All other HLA-B27 tetramers with Chlamydia-derived peptides such as peptide 138 did not bind synovial T cells in this patient (data not shown). In patient no. 2, 0.06% Chlamydia peptide 195-specific CD8⁺ T cells were detected by HLA-B27 tetramers. All other HLA-B27 tetramers with Chlamydia-derived peptides such as peptide 138 did not bind synovial T cells in this patient (data not shown). Peripheral blood from a blood donor with HLA-B27/EBV EBNA (258–266)-positive CD8⁺ T cells was used as a control.