Figure 5. CD8.4 preferentially enhances response to weak ligands.
Thymocytes from CD8WT and CD8.4 OT-I Rag2−/−β2m−/− mice were incubated with APCs loaded with varying concentrations of different peptides. After 24 hours, the percentage of CD69+ thymocytes was measured by flow cytometry. Response to OVA (A), T4 (B), and G4 (C) is shown. Mean ± SEM, n=4. Statistical significance was tested using Student's T test (1 tailed, unequal variance): * p<0.05, ** p<0.01. (D) CD69 response of CD8WT and CD8.4 OT-I DP thymocytes to different antigens was examined and EC50 values were calculated. Ratio of EC50 CD8WT/EC50 CD8.4 was plotted vs. EC50 CD8WT. Results show that CD8.4 thymocytes are preferentially more sensitive to weaker ligands, compared to CD8WT thymocytes. Red line shows the log-log line fit and the black lines represent 95% confidence intervals. See also Figure S4.