<prompt> Syncytium formation is the typical CPE produced by:-BK virusJC virusSV 40 virusMeasles virus  <response>: Syncytium formation is the typical CPE produced by Measles Virus. 1. Cytopathic effect CPE: It is defined as the morphological change produced by the virus in the cell line detected by light microscope. 2. Types of Cytopathic Effects CPE: Rapid crenation and degeneration of the entire cell sheet - Enteroviruses. Syncytium or multinucleated giant cell formation - Measles, RSV, HSV. Diffuse roundening and ballooning of the cell line - HSV. Cytoplasmic vacuolations - SV 40 Simian vacuolating virus-40. Large granular clumps resembling bunches of grapes - Adenovirus. 3. Syncytia is formed by fusion of an infected cells with neighboring cells leading to the formation of multi-nucleated enlarged cells. This event is induced by surface expression of viral fusion protein that are fusogenic directly at the host cell membrane. 