The antigen-presenting efficacy of γδ T cells from RA patients. Purified γδ T cells and B cells from RA patients were pre-treated with EBVgp110, HLA-DR4, TT and TTp, irradiated by γ-rays (4000 rad), and cocultured with CD4+ T cells (each well had 105 cells) at a ratio of 1∶2.5, 1∶5, 1∶10, 1∶20 or 1∶40. Seven days later, the proliferation was measured with the 3H-TdR method. The data were expressed as mean±s.d. APC, antigen-presenting cell; cpm, counts per million; EBV, Epstein–Barr virus; RA, rheumatoid arthritis; TT, tetanus toxin; TTp, tetanus toxoid peptide.