Figure 5.

DCs loaded with antigen can induce anergy. Human T cell clone 37 was incubated with DCs loaded with peptide P4 (at 10 μM) or 0.2 μg/ml of purified human TPO antigen. After 24 h, T cells were washed, rested, and challenged with DCs prepulsed with high doses of peptides P3 and P4. T cells preincubated with DCs only proliferated in response to peptides P3 and P4. Similar results were obtained if T cells were preincubated with DCs pulsed with the irrelevant MBP peptide or rested for up to 7 days (data not shown). T cells pretreated with DCs pulsed with P4 were anergized. T cells pretreated with DCs pulsed with TPO were also anergized, although anergy was more evident to the immunogenic peptide P3 (<10% of control). Proliferation to 100 μM of P4 was also significantly reduced (<40% of control). Experiments were also performed after purification of the pretreated T cells, obtaining similar profiles. The data are representative of three different experiments.