Functional analysis of T cells from CTLA4-Ig–injected mice. CD4 T cells were isolated from CTLA4-Ig–injected scurfy mice at day 22 (d22) and day 48 (d48) after birth. As a control, data from a phosphate-buffered saline–injected scurfy mouse at day 22 are shown. T cells were stimulated with anti-CD3 (□) or anti-CD3 and CD28 (■). (A) ³H-thymidine uptake of T cells after 72 hours of stimulation (proliferation) (mean ± SD, n = 3). (B) Interleukin-2, interleukin-4, interleukin-10, and interferon-γ production after 48 hours are shown. Results are representative of 3 CTLA4-Ig–injected mice (mean ± SD, n = 2).