Cell lysates of fresh PBMC and PHA-stimulated PBMC (PHA-blasts, on day 3) from two donors, PBMC from case no. 13, LN cells from case no. 14, Jurkat, and Hut102 were mixed with SDS sample buffer, boiled for 5 minutes, and then applied to electrophoresis through a 7.5% polyacrylamide gel. Proteins were transferred to a sheet of PVDF membrane and the membrane was incubated with 10 μg/mL 315 MoAb. The binding of the MoAb was detected as described in Materials and Methods.