Classical MHC I and GFAP double-staining in C57BL6/J and iNOS-/- mice, one week after axotomy. Observe that GFAP labeling in C57BL6/J (WT) mice is not co-localized with MHC I- (ER-Hr52) positive cells (C). Again, axotomized iNOS-/- mice did not express classical MHC I (E). (A and D) GFAP labeling on the lesioned side of C57BL6/J and iNOS-/- mice, respectively. Scale bar = 50 μm.