Maternal neurofascin-specific autoantibodies bind to structures of the fetal nervous system during pregnancy, but have no long term effect on development in the rat.
Neurofascin was recently reported as a target for axopathic autoantibodies in patients with multiple sclerosis (MS), a response that will exacerbate axonal pathology and disease severity in an animal model of multiple sclerosis. As transplacental transfer of maternal autoantibodies can permanently damage the developing nervous system we investigated whether intrauterine exposure to this neurofascin-specific response had any detrimental effect on white matter tract development. To address this question we intravenously injected pregnant rats with either a pathogenic anti-neurofascin monoclonal antibody or an appropriate isotype control on days 15 and 18 of pregnancy, respectively, to mimic the physiological concentration of maternal antibodies in the circulation of the fetus towards the end of pregnancy. Pups were monitored daily with respect to litter size, birth weight, growth and motor development. Histological studies were performed on E20 embryos and pups sacrificed on days 2, 10, 21, 32 and 45 days post partum.


RESULTS
Immunohistochemistry for light and confocal microscopy confirmed passively transferred anti-neurofascin antibody had crossed the placenta to bind to distinct structures in the developing cortex and cerebellum. However, this did not result in any significant differences in litter size, birth weight, or general physical development between litters from control mothers or those treated with the neurofascin-specific antibody. Histological analysis also failed to identify any neuronal or white matter tract abnormalities induced by the neurofascin-specific antibody.


CONCLUSIONS
We show that transplacental transfer of circulating anti-neurofascin antibodies can occur and targets specific structures in the CNS of the developing fetus. However, this did not result in any pre- or post-natal abnormalities in the offspring of the treated mothers. These results assure that even if anti-neurofascin responses are detected in pregnant women with multiple sclerosis these are unlikely to have a negative effect on their children.
Medical University Graz, Department of Neurology, Graz, Austria.
Sonja
S
Hochmeister
Medical University Graz, Department of Neurology, Graz, Austria.
Thomas
T
Pekar
University of Glasgow, Institute of Infection, Immunity and Inflammation, Glasgow, United Kingdom.
Maren
M
Lindner
Medical University Vienna, Brain Research Institute, Department of Neuroimmunology, Vienna, Austria.
Maja
M
Kitic
Medical University Graz, Department of Neurology, Graz, Austria.
Michaela
M
Haindl
Medical University Graz, Department of Neurology, Graz, Austria.
Maria
M
Storch
Medical University Graz, Department of Neurology, Graz, Austria.
Franz
F
Fazekas
University of Glasgow, Institute of Infection, Immunity and Inflammation, Glasgow, United Kingdom.
Christopher
C
Linington
D000818:Animals; D001323:Autoantibodies / Q000378:metabolism* / Q000494:pharmacology*; D015815:Cell Adhesion Molecules / Q000037:antagonists & inhibitors*; D004195:Disease Models, Animal; D005260:Female; D047109:Fetal Development / Q000187:drug effects*; D009414:Nerve Growth Factors / Q000037:antagonists & inhibitors*; D009420:Nervous System / Q000187:drug effects / Q000196:embryology / Q000378:metabolism*; D011247:Pregnancy; D051381:Rats
D001323:Autoantibodies; D015815:Cell Adhesion Molecules; D009414:Nerve Growth Factors; C504594:Nfasc protein, rat