Immunocytochemical quantitative study of alpha-fetoprotein in normal and neoplastic neural development.

The presence of alpha-fetoprotein (AFP) was studied in developing nervous tissues: rat cerebral cortex and neuroepithelial derivatives of a murine teratocarcinoma. AFP was localized by an indirect immunohistoperoxidase technique. Using serial dilutions of anti-AFP antibodies, the end-points of staining (minimal concentration of antibodies giving a positive labelling) were established. These points enabled the evaluation of the amount of stained AFP at different periods of development. In rat cerebral cortex, AFP showed one maximum amount on the 19th-20th day 'postcoitum' (in moderately differentiated structures), and two minima on the 13th-14th day (in primitively differentiated ones) and the 28th-29th day (in well-differentiated ones), respectively. Similarly, one maximum and two minima were established in the derivatives of teratocarcinoma imitating normal neural development.