eGFP and SAP expression following retroviral transduction of EBV–T-cell lines from XLP patients. (A) Flow cytometric analysis of EBV–T-cell lines from XLP patient P1 following transduction with eGFP/SAP-encoding retroviral construct shows 42% expression of eGFP in the EBV–T-cell line from patient 1 (S + CTLP1). (B) Immunoblot analysis using an anti-SAP antibody shows a 15-kDa protein expressed in EBV–T-cell lines from a control (CTLC1) and in these cells transduced using the eGFP/SAP retroviral vector (S + CTLC1) and a vector encoding eGFP only (G + CTLC1). The 15-kDa protein is also seen in XLP EBV–T-cell lines transduced with the eGFP/SAP retroviral vector (S + CTLP1) but not in EBV–T-cell lines transduced with the vector encoding eGFP only (G + CTLP1) or in untransduced EBV–T-cell lines (CTLP1).