Figure 4.

Linearity of assays. Triplicate samples of PBMC from a HLA-A2+ high-responding donor (#43) were serially diluted into PBMC from a known HLA-A2+ non-responder. The same non-responding donor was used for all assays. Unstimulated background was subtracted for each dilution point in CFC and ELISPOT assays. This background was uniformly low (< 0.08% for CFC and < 15 SFC per 2.5 × 10⁵ PBMC for ELISPOT) despite the used of allogeneic PBMC for the dilution. Note that the pp65_495–503 peptide response of this donor (#43) was much lower in ELISPOT compared to the other two assays.