EL case #19940 (Mag. 45K). A large putative virus factory is illustrated in which an assembly of regularly arranged membranes is embedded. Between the membranes are large numbers of individual dense particles. The membranes are not aligned in a straight line, indicating that the image is not due to blade chatter. The particles bound to membranes are interpreted to be the precursors to the putative complete virus, i.e., nascent VLP. Because of their high electron density and their size, which is smaller than that of the free particles, it is suggested that they consist of assemblies of nucleic acid without capsid protein. Similar membranes bearing VLP within putative virus factories were frequently observed in EL tissue. Bar = 1.2 μm.