Tau protein immunolocalization in fetal and adult human spinal cord.

In the present study, the monoclonal antibody Alz-50 has been used to determine and compare the immunohistochemical localization of phosphorylated tau proteins in the developing and normal adult spinal cord. At all stages of fetal life Alz-50 fiber immunoreactivity was observed in the dorsal roots, in the dorsal and dorsolateral funiculi, and in restricted regions of the dorsal horn. Alz-50 immunoreactivity was also demonstrated in the dorsal root ganglion neurons. In the adult spinal cord a consistent pattern of Alz-50 fiber immunoreactivity was localized in the superficial layers of the dorsal horn (lamina I and II) but not in dorsal and dorsolateral funiculi and in the dorsal root ganglion. Comparable results in fetal specimens have been obtained employing PHF-1, a monoclonal antibody generated against paired helical filament proteins from Alzheimer brains, while no significant immunostaining for PHF-1 was observed in the adult spinal cord. In addition, the staining with monoclonal and polyclonal anti-tau antibodies overlapped with that of Alz-50. The transient, selective pattern of Alz-50 and PHF-1 immunoreactivity may disclose some relevant functions of tau proteins during somatosensory pathway development.