Figure 6.

Impaired CD4⁺ T cell recall antigen response. (A and C) PBMCs from eight healthy controls (C1–C8), an R65C heterozygous family member (I.1), and the patient (P) were stimulated with PPD or PHA for 5 d. IFN-γ (A) or IL-10 (C) levels in the supernatant were measured by ELISA. The dotted lines indicate the limit of detection. One result representative of three independent experiments is shown. BCG+, BCG vaccinated; BCG−, no prior BCG vaccination; NS, nonstimulated. (B and D) IFN-γ (B) or IL-10 (D) production in response to various recall antigens was assessed as in A and C. Except for TT, which was provided as purified protein, the recall antigens were provided as virus-infected crude cell lysate. A lysate of uninfected cells tested in the same experiment did not trigger IFN-γ production (not depicted). The dotted lines indicate the limit of detection. One result representative of three independent experiments is shown. (E) CFSE-labeled PBMCs were incubated with the indicated recall antigens for 6 d. T cell proliferation was assessed by determining the proportion of cells with CFSE levels lower than the undivided peak. Results are shown for CD4⁺ T cells (CD3⁺CD4⁺). One result representative of three independent experiments is shown. (F) PBMCs from two healthy controls were incubated with 1 ng/ml of plate-bound anti-CD3 and Vero cells infected with retroviruses with an empty vector (Vero-Mock) or encoding OX40L (Vero-OX40L) for 3 d, or PPD or TT for 6 d. PBS, isotype antibody, or anti-OX40L antibody was added every other day to a concentration of 1 µg/ml. IFN-γ levels in the culture supernatant were measured by ELISA. Means and SEM from two experiments for one of the healthy controls are shown. **, P < 0.01; ns, not significant.