Human trypsin(ogen) 4-like immunoreactivity in the white matter of the cerebral cortex and the spinal cord

Human brain trypsin(ogen) 4-like (HT-4) immunoreactivity was localized in glial cells of human cerebral cortex and spinal cord. After a short post mortem delay (two hours), cortical and spinal cord regions were dissected, frozen or immersed into a fixative solution. Sections of 10 and 50 microm thickness were cut and immunostained by antibodies raised against recombinant human trypsin 4. HT-4-like immunoreactive glial cells and fibers were stained in the white matter, low to moderate levels of immunostaining were also observed in the matrix of the cerebral cortex and the spinal cord. To characterize HT-4-like immunopositive glial cells, alternate sections were immunostained for astrocytes and oligodendrocytes. HT-4 is present predominantly in astrocytes, but some of the oligodendrocytes and microglial cells may also contain this enzyme.