P-epitope is characteristic for the neural tissue of vertebrates.
Molecular Reproduction and Development
A A PreobrazhenskyV M Barabanov
Abstract
In a search for antigens immunologically related to chordin, a notochord-specific glycoprotein of sturgeneous fishes, extracts from 55 samples of human and rabbit tissues were tested for inhibition of [125I]chordin binding to rabbit polyclonal antibodies. The strongest inhibition was observed with brain extracts of both species. Human, chicken, rabbit, and newt brain extracts also inhibited chordin binding in liquid phase to monoclonal antibodies (MAbs) against the P-epitope, the most immunogenic epitope of this glycoprotein. Immunohistochemical studies done on human and chicken embryos, newt, sterlet, and sturgeon embryos, larvae, and juveniles revealed a strong immunoreactivity of the brain, spinal cord, and tissue of the peripheral nervous system with an anti-P MAb. Other tissues, with several exceptions, showed a negative reaction in immunohistochemical experiments. The authors found that the P-epitope is ontogenetically expressed in the neural tissue of chicken, newt, and sterlet at the period of cytodifferentiation. Gel chromatography of human, chicken, and newt brain extracts showed that in each case the P-epitope was associated with a polydisperse macromolecular material of similar size. These antigens were designated a...Continue Reading