Sensitive micro in situ fluorescent focus assay for detection of murine xenotropic retroviruses

A sensitive micro in situ fluorescent focus assay (mISFA), which utilizes cell monolayers fixed on a plastic surface, was developed for the detection of NZB xenotropic type C retroviruses grown in mammalian cell lines. The mISFA technique is an easier, more rapid and less expensive assay than other biological tests used to detect these viruses; it gives a more precise viral titer and is slightly more sensitive. This technique allows extension of host-range investigations to include any growing cell cultures and is applicable to various virus-host cell systems.