Figure 2

Local and immune responses to zymosan at day 25. (a) Periodic acid Schiff staining shows the persistence of zymosan particles (arrow) within the synovial membrane in zymosan-induced arthritis (ZIA). Original magnification ×100. (b) In vitro lymph node mononuclear cell proliferation in response to zymosan at day 25 of ZIA and in naive mice. Single-cell suspensions were incubated with 4 μg/ml zymosan. Concanavalin A (ConA) was used as a non-specific mitogen. (c) Antibody production against zymosan in zymosan-treated mice compared with naive mice measured by enzyme-linked immunosorbent assay (ELISA). The results are expressed as a ratio of the amount of zymosan-specific IgGs (in arbitrary units) in murine serum to total IgGs (also in arbitrary units) (P < 0.05). (d) Interferon-γ (IFN-γ) production by zymosan-stimulated and unstimulated lymph node cells of WT ZIA and naive mice in culture. IFN-γ was measured by specific ELISA. n.d., not detectable.