Figure 4

T-cell hyporesponsiveness to type II collagen in collagen-induced arthritis-susceptible mice with LF-treated dendritic cells. Day 4 bone-marrow-derived dendritic cells (DC) cultured in granulocyte-macrophage colony-stimulating factor/IL-4 were treated with 5 μg/ml LF or PBS alone, and fresh medium was added every 24 hours. On day 7, both LF-treated DC and control PBS-treated DC were pulsed with type II collagen (CII) (10 μg/ml) for 24 hours. On day 8, CII-pulsed cell cultures were activated with TNFα/lipopolysaccharide for the next 24 hours, and 5 × 10⁶ cells/mouse were injected intraperitoneally into DBA/1 LacJ mice primed with CII (200 μg/mouse in complete Freund's adjuvant) 12 days earlier. Twenty-one days after priming, the mice were boosted intraperitoneally with the same dose of CII in PBS. At the end of clinical assessment of collagen-induced arthritis development, the mice were sacrificed and T cells from lymph nodes were isolated. A CII-specific response from different groups of animals was performed by proliferation, as described in Materials and methods. Lymphocytes were restimulated in vitro with different concentrations of CII (5, 25, and 50 μg/ml) or PBS alone and a ³H-labeled thymidine incorporation was measured. Results represent one of three experiments (n = 4 per group/experiment). *P < 0.05 versus the control DC-treated group. cpm, counts per minute.