Proliferating cell nuclear antigen (PCNA) expressed in human leptomeninges

Here we report on the presence of proliferating cell nuclear antigen (PCNA) in human leptomeninges from 35 normal subjects with ages ranging from 57 to 94 years. Strong immunoreactivity with PC10 (a monoclonal antibody to PCNA) was detected in the nuclei of meningothelial cells, smooth muscle cells of leptomeningeal vessels, and ependymal cells, An immunoblot of leptomeningeal homogenate with PC10 showed the presence of a single band at 35 KD, the expected molecular mass of PCNA, Ki-67, another marker for cell proliferation, was undetectable in human leptomeninges. These observations point to isolated PCNA expression in tissue in which cells are not actively proliferating.