Figure 3

A12-responsive T cells are not Tregs. Inguinal lymph node cells from DR1 Tg mice immunized 10 days earlier with A12/CFA (left panel), A2/CFA (middle panel), or Ova/CFA (right panel) were cultured directly ex vivo with anti CD25, CD4⁺, VB8⁺, VB14⁺, and intracellular FoxP3. Selective gating was performed on the CD4⁺, VB8⁺VB14⁺ cells. Before intracellular staining, a sample of the A12-specific cells was stained with DR1-A12 tetramer to confirm that the VB8⁺, VB14⁺ population was enriched for tetramer⁺ cells (15% tetramer⁺). The experiments were repeated after 4 days of culture with the A12 peptide in vitro, and the results were similar to those shown. These data indicate that the numbers of Foxp3⁺, CD25⁺ Treg cells remain at background levels after immunization with A12/CFA.