Intravital Two-Photon Imaging of Adoptively Transferred B Lymphocytes in Inguinal Lymph Nodes

Intravital two-photon imaging allows the observation of immune cells in intact organs of live animals in real time. Recently, several studies using two-photon microscopy have detailed the motility of mouse B and T lymphocyte within lymph nodes and have shown a dependence upon chemokine receptor signaling for the basal velocity of the cells. For, example, T cells from Gnia2 ^−/− mice, deficient in the heterotrimer G-protein Gα subunit G_αi2 have markedly impaired chemokine-triggered chemotaxis. In vivo these cells have reduced motility and impaired positioning within lymph nodes. Gnia2 ^−/− B cells exhibit similar defects. In addition, B cells from Rgs1 ^−/− mice, deficient in a major negative regulator of G_αi , have a more robust motility than do wild–type B cells. Here, we describe procedures for visualizing the behavior of fluorescently labeled and adoptively transferred B lymphocytes within the inguinal lymph node of live mice.