Microtubule-associated protein 4 antibody: a new marker for astroglia and oligodendroglia.

An antibody to a 240,000 dalton microtubule-associated protein, microtubule-associated protein 4, was used to illustrate the distribution of this protein in semi-thin sections of the central nervous system. Immunofluorescence microscopy indicated that microtubule-associated protein 4 was restricted to non-neuronal elements of the brain and spinal cord. Astrocytes, oligodendrocytes and "specialized" glia, including tanycytes, Bergmann glia and Muller cells, contained microtubule-associated protein 4. This distribution of microtubule-associated protein 4 in neural tissue in distinct from that described for the other major brain microtubule-associated proteins, microtubule-associated protein 1 and microtubule-associated protein 2. The reactivity of MAP 4 antibody with these glia demonstrates the antigenic relatedness of these cells and further distinguishes glia from other elements of the nervous system.