The allogeneic T-cell stimulatory capacity of SP37A3 cells depends on their state of differentiation. Titrated numbers of irradiated DCs were cocultured with 3 × 10⁵ nylon wool–enriched T cells of BALB/c mice for 4 days in triplicate cultures. T-cell proliferation was assessed as uptake of [³H] thymidine for the final 16 hours of culture. (A) BM-DCs were used either at an immature state, or were matured by addition of LPS (1 μg/mL for 48 hours). In parallel cultures, DEX was applied at 10⁻⁶ M and 10⁻⁵ M starting on day 3 of culture, and stimulation with LPS was performed as described. (B) Immature and mature SP37A3 cells were generated as described (Figure 1). In parallel cultures, DEX was coapplied during induction of maturation. Data represent mean ± SEM of triplicate cultures and are representative of 4 (A) and 5 (B) independent experiments. *P < .05 compared with immature and DEX-cotreated DCs (10⁻⁵ M, 10⁻⁶ M); ⁺P < .05 compared with DEX-cotreated DCs (10⁻⁵ M, 10⁻⁶ M). For the sake of clarity, indication of distinct levels of significance was omitted. (C) A micrograph of SP37A3 cells stimulated in the presence of 10⁻⁵ M DEX, as described in panel B. The image was captured as described in Figure 1. (D) The relative allogeneic T-cell stimulatory capacity of differentially conditioned SP37A3 cells was determined. Experiments were performed as described for panel B. Results obtained with 1.7 × 10⁴ immature, mature, and DEX-treated SP37A3 cells are shown. The respective T-cell proliferation induced by mature SP37A3 cells was set to 1 (horizontal dashed line). Data represent mean ± SEM of 5 independent experiments. *P < .05; **P < .01; ***P < .001.