Pharmacokinetics and tissue distribution of NMO-IgG following IP injection. A. Serum concentration of human IgG quantified by ELISA at 1, 2, 4, 6, 8, 24 and 48 h after intraperitoneal injection of NMO-IgG or control IgG (each 750 μg) (S.E., 3 rats per group). B. Tissue distribution of NMO-IgG at 24 h after injection of NMO-IgG or control IgG. AQP4 immunofluorescence (green), human IgG (with secondary anti-human antibody, red) and activated complement (C5b-9). Arrows indicate basolateral membrane in kidney inner medullary collecting duct epithelial cells, basolateral membrane of gastric parietal cells, basolateral membrane of tracheal surface epithelial cells, and the plasmalemma in skeletal muscle. C. AQP4 and human IgG staining in retina, brain, spinal cord and optic nerve in same rats as in B. D. AQP4, human IgG and C5b-9 staining in area postrema in same rats as in B.