Figure 2

Microglial activation induced by Th1-cell transfer depends on IFN-γ. Adoptive transfer of Th1-conditioned cells after SCI leads to activation of MG/MΦs at the injured site, and microglial activation is dependent on ifn-γ in transferred Th1 cells. (a) Immunohistochemistry for MG/MΦs labeled with anti-Iba1 antibody. Spinal cords removed on day 10 after SCI were cut transversely. The section at 0 mm corresponds to the epicenter of the contusion and the distance shown is caudal from the epicenter. Scale bar, 500 μm. (b) Higher magnification views of (a). Scale bar, 100 μm. (c) Representative flow cytometry profile of MG/MΦs that accumulated in the spinal cord on SCI day 6, 2 days after the injection of PBS or cultured T cells. Upper dot plots indicate the side-scatter/forward-scatter profile by which CD11b/CD45 profiles were gated. In lower dot plots, CD11b ^intermediate CD45 ^intermediate corresponds to MG, whereas CD11b ^high CD45 ^high corresponds to MΦs. The leftmost dot plots indicate a profile using isotype-matched immunoglobulins as a control. (d) The number of MG or MΦs that accumulated in the spinal cord on day 6 after SCI, 2 days after the injection of PBS or Th1-conditioned cells. PBS, n=3; Th1, n=4; Th1 ifn-γ^−/−, n=3. Leukocytes isolated from the spinal cords of two to four mice were analyzed in each experiment. *P<0.05 (one-way ANOVA with Bonferroni post-test)