Figure 1.
T Cells Migrate along Tracks that Extend between the T Zone and Red Pulp Compartments
(A) Two-photon laser scanning microscopy (TPLSM) of spleens from hCD2-DsRed mice (endogenous T cells, red) transferred with GFP+ B cells (green). Green line indicates the approximate location of the border between the marginal zone (MZ) and follicles (FO).
(B) Closer view of two areas in the MZ region (yellow boxes in A). The movement of T cells (blue arrow and line) and B cells (white arrow and line) over time is highlighted. See also Video S1.
(C) Circularity index and velocity of endogenous T cells migrating in the MZ and red pulp (RP). The x axis represents distance of cells from the MZ-FO border. Each circle represents the average circularity or velocity of cells assessed in one mouse. Error bars represent SEM. Data in (A–C) represent at least four independent experiments.
(D and E) TPLSM of Actin-CFP chimeras reconstituted with a 1:1 mixture of bone marrow from CD19cre−cre/YFP (follicular B cells, green) and hCD2-DsRed (T cells, red) mice. Collagen (detected with second harmonic) and CFP signals were collected in the same detector (blue). 69-μm z-projection (D) and time projection (E) views are shown. The dashed white line indicates approximate location of the MZ-FO border. See also Video S2.
(F) Histological analysis of fixed spleen sections of hCD2-DsRed mice (endogenous T cells, red) adoptively transferred with GFP+ B cells (green) and stained for CD169 (gray). Images were taken 24 h after B cell transfer. Tracks of T cells are highlighted with a white line. Blue lines indicate location of MZ BCs.
(G) Left, a snapshot of a 2D slice from a TPLSM sequence illustrating cell shape. Bottom, examples of masks drawn around T cells to calculate circularity. Right, circularity index of T cells migrating in the red-pulp (RP) and on T cell tracks (“T-track”). Error bars represent SD. Data in (D–G) represent at least three independent experiments. ∗∗∗∗p < 0.0001.