Effect of CD3/CD28 culture on phenotype and IFN-γ induction in patient T cells. (A) In vitro phenotype of lymphocyte culture: patient mononuclear cells obtained from steady-state pheresis (day 0), after partial depletion of monocytes via adherence to magnetic beads (PMD), and after 7 or 13 days of culture via CD3/CD28 stimulation. Cells were analyzed by flow cytometry for CD3⁺CD4⁺ cells (open bars), CD3⁺CD8⁺ (hatched bars), and total CD3⁺ cells (solid bars) as described in “Patients, materials, and methods”. Shown is a representative patient, UPN26. (B) Effect of culture process on IFN-γ expression. Study patient T cells obtained at baseline (open bars) or after 13 days of culture with CD3/CD28 beads (solid bars) were examined by flow cytometry for intracellular cytokine staining. Cells were collected from culture and analyzed as described in “Patients, materials, and methods.” The percent of CD3⁺, CD3⁺CD4⁺, and CD3⁺CD8⁺ cells staining for IFN-γ is shown for a representative patient, UPN26.