Читать книгу Principles of Virology - Jane Flint, S. Jane Flint - Страница 83

The fluorescent-focus assay, a modification of the plaque assay, can be done more rapidly and is useful in determining the titers of viruses that do not form plaques. The initial procedure is the same as in the plaque assay. However, after a period sufficient for adsorption and gene expression, cells are made permeable and incubated with an antibody raised against a viral protein. A second antibody, which recognizes the first, is then added. This second antibody is usually conjugated to a fluorescent molecule. The cells are then examined under a microscope at an appropriate wavelength. The titer of the virus stock is expressed in fluorescent-focus-forming units per milliliter. When the gene encoding a fluorescent protein is incorporated into the viral genome, foci may be detected without the use of antiviral antibodies.