Comparison of CD4 responses to ICP4, HSV-1 VP22, and HSV-2 VP22. Frozen samples from several subjects were tested in the CD4 IFN-γ ELISPOT assay using peptide pools for ICP4 (left column), VP22 from HSV-2 (middle column) and VP22 from HSV-1 (right column). Subjects (1,2,7,10,11,12) were chosen based on serostaus (HSV-1/2, HSV-1, HSV-2) and designated as having high (H) or low (L) recurrence rates. Number of ELISPOTS/well is plotted on the Y-axis. The amount of cells placed in each well are those recovered from an original 0.5 million PBMCs.