Plaque formation in virus is done for:
Ans. (c) Determining infectivity of virus Ref. Ananthanarayan 8/e, p 435, 9/e, p 437 By By Quantal assay Quantitative Infectivity assay of virus Electron Hemagglutination * Indicates presence or Measure actual number of infectious microscopy inhibition absence of infectious viruses. paicle in inoculum * Titre is usually expressed as '50 percent infectious dose" (ID50) per ml calculated by statistical methods e.g. Reed and Muench Plaque assay or monolayer cell culture Transformation assay For oncogenic virus Pockassay on choronic allan-toic membrane (CAM) e.g. variola, vaccina herpes virus monkey pox, cow pox Plaque assay: Each infectious paicle give rise to a localized focus of infected cells that can be seen with naked eye. Such foci are knows as plaque and each plaque indicates an infectious virus. Titre is usually expressed as
Isolation and typing of viurses
Cloning separation of specific viruses
Determining infectivity of virus
Assessing multiplication of virus