Glomerular lesions in Rag2^–/– mice 13 days after they received splenocytes. (a) No light microscopic abnormality in a glomerulus from a mouse that received 1 × 10⁷ anti-MPO splenocytes. (b) Moderate (2+) endocapillary hypercellularity in a mouse that received 1 × 10⁸ anti-BSA splenocytes. (c) Segmental fibrinoid necrosis (arrow) in a mouse that received 1 × 10⁸ anti-MPO splenocytes. (d) Cellular crescent (arrow) in a mouse that received 1 × 10⁸ anti-MPO splenocytes. (e) Immunofluorescence staining for fibrin in a crescent in a mouse that received 1 × 10⁸ anti-MPO splenocytes. (f) Predominantly mesangial moderate (2+) immunofluorescence staining for IgG in a mouse that received 1 × 10⁸ anti-BSA splenocytes. Periodic acid Schiff stain for light microscopy is shown.