Figure 4.

Anergy induction in the absence of costimulation. Human T cell clone 37 was incubated in the absence of APC with 10 μM of peptide P3, 10 μM of peptide P4, and medium alone. After 24 h, T cells were washed, rested, and challenged with DCs prepulsed with increasing concentrations of peptides P3 and P4. T cells preincubated with medium proliferated in response to peptide P3 and a high dose (100 μM) of peptide P4. Similar results were obtained if T cells were preincubated with the irrelevant MBP peptide or rested for up to 7 days (data not shown). T cells pretreated with peptides P3 or P4 in the absence of APC did not respond to a further peptide stimulation (Middle and Right). T cell proliferation to exogenous IL-2 confirmed that T cells were still viable. All results are representative of five different experiments.