Figure 3.

(A) Stimulation index (SI) distribution for in vitro T cell receptors (TCRs). The SI is calculated as the logarithm (base 2) of the abundance in the in vitro culture with medium alone (empty bars) or stimulated with 100 µg/ml paraphenylenediamine (PPD)–human serum albumin (HSA) (filled bars) relative to the abundance in the ex vivo sample. The abundance of the TCRs that are absent from the ex vivo sample is estimated as 1 (mean abundance in ex vivo samples is 1.3). (B) The number of TCRs with a SI > 3 (i.e., more than eightfold expanded in in vitro culture) for cultures in medium, HSA, or PPD–HSA.