Although these three antigens induced in vivo recall responses with characteristically different levels of IL-2, IFNc and IL-4, all three antigens induced substantial production of AR in the activated (CD154+) cells ( Figure 5D ). Similar results were obtained with cells from multiple subjects, although the magnitudes of the antigen responses were variable for all cytokines. Thus AR can be expressed by all the conventional defined subsets of T cells that we have tested, including CD4 and CD8, naïve and memory, Thpp, Th1 and Th2.