ease are graphically presented in Fig. 1: (A) JC virions as they assemble in the nucleus of an infected cell in the brain; (B) glial cells, cultured from human brain, which are the targets of virus infection; (C) histopathological plaque lesion of white matter, stained for myelin, that results from that infection; (D) hematoxylin and eosin stain of cells in the lesion identified as macrophages (m) and astrocytes (a); and (E) plaques of demyelinated white matter which represent the neurological impairments characteristic of PML, shown here by magnetic resonance imaging (MRI). The term PML was originally used in 1958 to describe extensive demyelination associated with chronic lymphocytic leukemia (CLL) and Hogdkin's lymphoma (14). However, accounts of similar pathology in patients with dementia were detailed as early as 1930 by Hallervorden (85). A 49 on September 7, 2020 by guest http://cmr.asm.org/ Downloaded from Host Range Studies of JCV in Non-Brain-Derived Cells By using laboratory measurements of JCV growth such as hemagglutination activity, other cells from human and other species were tested for JCV susceptibility. At first, human embryonic kidney, lung, amnion, liver, and intestine were