Detection of the

lacZ gene in the PBMCs of in utero–transduced sheep prior to and at day 68 postimmunization with β-gal. Reagent (R) consisted of all the constituents of the PCR reaction mixture except template DNA. Negative control (−) was DNA isolated from PBMCs of a normal control sheep. Positive control (+) consisted of DNA isolated from a human fibroblast cell line that had been transduced with the same vector and subsequently diluted in normal sheep DNA.