A. Vγ4Vδ4+ cell numbers obtained from lymph nodes of B6.TCRβ−/− mice immunized by intradermal injection of CFA on days 0 and 14, and sacrificed on day 19. Error bars show s.d. B. B6.TCRβ−/− mice were treated as in A, and lymph nodes cells analyzed by flow cytometry. The percent of Vγ4+ cells co-expressing Vδ4 (left), the percent of IL-17A+ cells among Vγ4Vδ4+ cells (center), and the percent of CD44-high cells among Vγ4Vδ4+ cells (right), are shown. For each condition, 5–7 mice were tested, except for IL-17A expression by naïve Vγ4Vδ4+ cells, which is shown for comparison and represents lymph nodes from two mice that were pooled.