Expression of Jak2, Tyk2, and STAT3 by PBMCs. PBMCs obtained from a healthy control subject (lanes 1-2) and a patient with lymphoma 3 months after transplantation (lanes 3-4) were incubated with or without IL-12 100 U/mL for 1 hour as indicated, lysed, resolved by SDS-PAGE, transferred to nitrocellulose membranes, and immunoblotted using antibodies specific for Jak2, Tyk2, STAT3, or GAPDH as indicated. Location of the specific band for Jak2 is indicated by the arrow. Results are representative of those seen with 4 control samples (4 for Jak2, 2 for Tyk2 and STAT3) and 4 patient samples (4 for Jak2, 2 for Tyk2, 3 for STAT3) that were tested.