Different activation signals such as PHA, anti-CD3, and anti-CD3 plus anti-CD28 antibodies result in similar transduction efficiency and identical level of transgene expression.

(A) Autofluorescence of transduced cells stained with FITC-conjugated goat antimouse antibody. (B) Transduction efficiency measured by cytofluorometric analysis for ΔLNGFR expression after cell-free, supernatant-mediated transduction. (C) ΔLNGFR expression of the same subpopulation of lymphocytes after immune selection and 14-day culture from initial activation.