T cell specificity to the CII259-273 epitope and its posttranslationally modified forms. B10.Q and B10.DR4.Ncf1*/* mice were immunized with 100 μ g CII in CFA (day 0) and boosted 21 days later with 50 μ g CII in IFA. Five to ten mice per group were sacrificed at day 15, 35, 50 and 65 postimmunization. Single cell suspensions from collected inguinal lymph nodes were incubated in vitro with collagen peptides or (conA) for 96 h. Culture supernatant was then used for measurement of INF-γ content. (A) T cell recall response in B10.DR4.Ncf1*/* strain. The symbol '*' marks responses that are significantly higher than the GalOK264 response. *, P <.05; **, P <.01; ***, P <.001. Mean IFN-γ values for the conA stimulated positive control: d. 15 - 10.276 ± 0.899 ng/ml; d. 35 - 4.386 ± 0.269 ng/ml; d. 50 - 15.915 ± 1.349 ng/ml; d. 65 - 7.996 ± 1 ng/ml. (B) CII-specific T cell response in B10.Q mouse strain. The symbol '†' marks significantly lower responses compared to GalOK264 response. †, P <.05; ††, P <.01. Mean IFN-γ values of the positive control: d. 15 - 1.927 ± 0.321 ng/ml; d. 35 - 7.004 ± 0.231 ng/ml; d. 50 - 4.569 ± 0.631 ng/ml; d. 65 - 2.4 ± 0.3 ng/ml. Background values (IFN-γ levels secreted by cells cultured in standard medium without CII peptides or conA) are subtracted from the presented data. All data represent mean ± SE of triplicates. CFA, complete Freund's adjuvant; con A, concanavalin A; CII, collagen type II; IFA, incomplete Freund's adjuvant; IFN, interferon.