ON THE LOCALIZATION OF THY-1-LIKE IMMUNOREACTIVITY IN THE RODENT AND HUMAN NERVOUS-SYSTEM

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  • 1 January 1986
    • journal article
    • research article
    • Vol. 64  (2-3) , 109-117
Abstract
The neuronal localisation of the surface glycoprotein Thy-1 was studied using the adult mouse iris whole-mount preparation. Polyclonal antibodies to Thy-1 and indirect immunohistochemical techniques were used on fixed tissues. In the adult intact mouse iris a plexus of delicate bundles and fibres was found in both the dilator and sphincter regions. Ovoid negative spots along the bundles were numerous, probably indicating the location of supportive cells. The ciliary body contained strongly immunoreactive bundles oriented in radial and circular patterns. Numerous Thy-1-positive mast cells were found in the irides. All Thy-1-immunoreactive fibres disappeared in intraocular iris transplants after 4 days, leaving only the Thy-1-positive mast cells. A Thy-1-positive fibre plexus reappeared in intraocular iris transplants after 4 weeks, strongly indicating that Thy-1-immunoreactive fibres in adult mouse irides are associated with the nerve fibres and not with their supportive tissue. Distribution of Thy-1-like immunoreactivity in the developing human nervous sytem is presented for the first time, and its temporal changes are followed from eighth gestational week to adulthood. At eight weeks the spinal cord and lower brain stem seemed to show virtually no immunoreactivity. At 10 and 31 weeks gestational age immunoreactivity was found preferentially in white matter areas with a granular appearance, becoming more densely aggregated at the later stage. Two months postnatally the internal capsule was strongly positive in an otherwise negative neuropil, only to disappear completely in the adult brain. Cerebellum contained Thy-1-positive fibres in both grey and white matter in a pattern already similar to that in the adult, whereas in cortex cerebri a sparser and more immature distribution of the Thy-1-immunoreactivity could still be seen at the age of 5 years. Hippocampus contained varicose positive nerve fibres in the white matter at 31 weeks of gestation. The granular appearance of the immunoreactivity disappeared until adulthood, whereas the fibrous structures spread to all layers of the hippocampal formation. Radioimmunoassay of the Thy-1-glycoprotein in cerebral and cerebellar cortices during ontogeny correlated well with the morphologically visualized Thy-1-immunoreactivity. The results from the developing human CNS also correlate well between regional differentiation processes, such as terminal arborization and synapse formation in target areas, and the localization of Thy-1-like immunoreactivity.