Figure 3.

Analysis of the induction of actively induced EAE in irradiated BM chimeric mice. (A–D) In BM chimeric mice, the parenchymal microglial cells are host derived and the infiltrating leukocytes are predominantly donor derived. Mice were irradiated and reconstituted with CD45.1-congenic BM cells. Engraftment took place over 2 mo. CNS cells of nonimmune mice were stained with either the (A) host (CD45.2) or (B) donor-congenic CD45.1 marker. C and D show the degree of chimerism of CNS-infiltrating leukocytes in BM chimeric mice with EAE induced by immunization with MOG_35–55 in CFA. (E and F) The lack of CD40 expression on radioresistant cells in the host does not influence peripheral T cell responses. After 2 mo of recovery, mice were immunized with MOG/CFA and LNs were removed 5 d later. Recall proliferation (E) and IFN-γ secretion (F) in response to either 100 μg MOG peptide or irrelevant PLP peptide was assessed in vitro. (G) The lack of CD40 in the CNS reduces EAE. CD40^+/+→CD40^+/+, CD40^+/+→CD40^−/−, CD40^−/−→CD40^+/+, and CD40^−/−→CD40^−/− mice were produced, allowed to recover for 2 mo, then immunized with MOG_35–55 in CFA as described above and scored for clinical disease (n = 5/group; representative of four individual experiments). The clinical score of CD40^+/+→CD40^+/+ vs. CD40^+/+→CD40^−/− is statistically significantly different (P < 0.05). EAE was scored over 24 d. (H and I) The lack of CD40 expression in the CNS reduces the extent of leukocyte infiltration. 7 d after disease onset, leukocyte infiltration into the CNS of (H) CD40^+/+→CD40^+/+ and (I) CD40^+/+→CD40^−/− mice was analyzed as described.