Subsets of murine CD4+ T cells localize to different areas of the spleen after adoptive transfer. Naive and T helper 1(T(H)1) cells, which express the chemokine receptor CCR7, are home to the periarteriolar lymphoid sheath, whereas activated T(H)2 cells, which lack CCR7, form rings at the periphery of the T cell zones near B cell follicles. Retroviral transduction of T(H)2 cells with CCR7 forces them to localize in a T(H)1-like pattern and inhibits their participation in B cell help in vivo but not in vitro. Thus, differential expression of chemokine receptors results in unique cellular migration patterns that are important for effective immune responses.
