Figure 1.

CD4⁺ T cells become activated in AND TCR⁺ mice in the absence of CTLA-4. Representative flow cytometry data of the lymph node cells from AND TCR⁺ CTLA-4^−/− and littermate control animals. The expression of AND TCR transgene (A) and the phenotype of the CD4⁺ lymph node T cells (B) from an 8-week-old AND TCR⁺ CTLA-4^−/− mouse and littermate control. The absolute number of the CD4⁺ T cells is indicated.