Fig. 5

Myeloid cells at the chronic active lesion rim express PD-1. Using human post-mortem MS tissue (n = 5), (A) NAWM and (B) chronic active lesions were cryopreserved, sectioned, and labeled with MBP and Iba1 and imaged using confocal microscopy. Once NAWM, chronic active lesion rims (LR), and the lesion core (LC) were identified, (C, E) NAWM and (D, F) lesion rims were labeled for GFAP, Iba1, and PD-1 at (C, D) 20 × and (E, F) 63 × magnification using confocal microscopy. G IMARIS rendering of GFAP, Iba1, and PD-1 within the chronic active lesion rim was generated to identify PD-1 surface expression. H Total PD-1 area was quantified and I the colocalization of GFAP and Iba1 with PD-1 in both NAWM and the chronic active lesion rim was assessed. Data represent the mean ± SEM and were analyzed using a (H) two-tailed Student’s t test or (I) one-way ANOVA. **P < 0.01, ****P < 0.0001