Reactivity of CLL rAbs with the native pUL32. Recombinant pUL32, pUL29, and untransfected 293FT cell sonicates were probed in parallel with 2-fold serial dilutions of CLL rAb CLL69B (stock solution, 10 μg/mL; A), CLL rAb CLL69D (stock solution, 10 μg/mL; B), CMV-specific immune serum (Se CMV+; C), and HSV-2–specific immune serum (Se HSV+; stock dilution of serum samples, 1:1500; D). Cell sonicates were harvested at 48 hours after transfection for EIA analysis with equal amounts of total protein used. Ab preparations were used at 1 to 10 μg/mL and were titrated to avoid saturation of binding sites. All experiments were done in duplicate and each Ab was tested against the 3 different protein preparations in parallel on the same EIA plate.