Time course of penetration of xenogeneic IgG into the central nervous system of the neonatal rat: an immunohistochemical and radionuclide tracer study.
We investigated the penetration of rabbit IgG into the brain and spinal cord of newborn rat pups and compared them to mature rats using immunohistochemical and radionuclide techniques. Following intraperitoneal injection with rabbit IgG and perfusion fixation at various intervals, rabbit IgG was found to penetrate into the parenchyma of the neuraxis of neonatal rats and to establish much higher concentrations than was found in mature rats. Immunohistochemical studies revealed no evidence of significant extravasation of serum proteins from the vasculature. For any given survival interval studied, there was no significant difference in appearance and intensity of immunohistochemical staining or the amount of radiolabeled IgG measured between different areas of the brain and spinal cord. Electrophoresis of radioactive proteins extracted from the brains of neonatal rats injected with radiolabeled IgG confirmed that IgG penetrates into the brain parenchyma as the whole molecule. These results validate the use of systemically administered rabbit IgG for studies of brain development in neonatal rats. They also have implications for the pathogenesis of congenital central nervous system anomalies in which maternal autoimmune IgG may affect brain development after being transferred to the fetus or neonate.
Fabian
R H
RH
Department of Neurology, University of Texas Medical Branch, Galveston, 77550.
Hulsebosch
C E
CE
D000818:Animals; D002490:Central Nervous System / Q000000981:diagnostic imaging / Q000378:metabolism*; D007074:Immunoglobulin G / Q000008:administration & dosage* / Q000032:analysis; D007150:Immunohistochemistry; D007267:Injections; D007457:Iodine Radioisotopes; D011877:Radionuclide Imaging; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors
D007074:Immunoglobulin G; D007457:Iodine Radioisotopes