Fig. 5.

Topotecan enhances the T cell stimulatory capacity of unstimulated DCs, but impairs their stimulation-dependent functional activation, and affects T cell polarization. DCs were differentiated, stimulated, and treated with TPT as described. a Titrated numbers of irradiated DCs were cocultured with 10⁵ immunomagnetically sorted allogenic CD4⁺ T cells in 0.2 ml culture medium in triplicate cultures for 4 days. T cell proliferation was assessed by the uptake of [³H] thymidine for the final 16 h of culture. CD4⁺ T cell proliferation induced by 2 × 10⁴ stimulated DCs was arbitrarily set to one. Data represent the mean ± SEM of four independent experiments. b, c Supernatants were collected from DC/T cell cocultures (DC/T cell ratio 1:5) on day 4 of culture. IFN-γ, IL-5, and IL-10 contents were assayed by ELISA. b The Th2/Th1 bias was calculated by the IL-5/IFN-γ ratio; with the ratio in cocultures containing stimulated DCs, it was arbitrarily set to 100 %. c The relative IL-10 content in DC/T cell cocultures is shown with the content of IL-10 in cocultures containing unstimulated DCs left untreated or treated with TPT arbitrarily set to 100 % each. Data represent the mean ± SEM of seven independent experiments. a–c Statistical significance *stimulated versus unstimulated DCs, TPT-treated versus untreated DCs at unstimulated (#) or stimulated (+) state (^#,+ P < 0.05, **^,##,++ P < 0.01, ***^,###,+++ P < 0.001)