Presentation of citrullinated peptides by freshly harvested APCs. (A–F) IL-2 production from CD11c⁺ cells isolated from thymi (A and B), spleen (C and D), and splenic CD19 ⁺ cells (E and F). A, C, and E show response to the 48–62-Cit61 peptide by Granny, whereas B, D, and F show response to the unmodified 48–62 by 3A9. (G and H) The response to CD11c⁺, CD11b⁺ cells purified from the popliteal lymph nodes of mice 24 h after immunization with 10 nmol HEL and tested against (G) Granny or (H) 3A9 is shown. Data from each panel are representative of at least two independent experiments, and each data point represents duplicate wells. At least three mice were used in each experiment. Error bars indicate SEM.