CD134 is a type I integral membrane protein. This receptor is expressed on activated CD4 and CD8 T cells and B cells. The CD134 binds to CD134 ligand (CD252) to provide a costimulatory signal that is independent of CD28. CD134 is involved in coordinating CD4 T cell selection, migration and cytokine differentiation in T helper (Th)1 and Th2 cells. CD134 is also involved in the stimulation of T cells, T dependent humoral response and generation of optimal CD4 T cell responses in vivo and in vitro. CD134 is expressed on activated CD4 T lymphocytes, and its ligand, CD134L, is found preferentially on activated B cells. Engagement of CD134 with its ligand, CD134L, delivers a strong costimulatory signal to effector T cells. Primary antibodies are available purified, or with a selection of fluorescent CF® Dyes and other labels. CF® Dyes offer exceptional brightness and photostability. Note: Conjugates of blue fluorescent dyes like CF®405S and CF®405M are not recommended for detecting low abundance targets, because blue dyes have lower fluorescence and can give higher non-specific background than other dye colors.