Localization of the major group-specific protein (p27) of avian tumor viruses by immunofluorescence in chicken cells and tissues.

An immunofluorescence technique was developed for the major group-specific (gs) p27 antigen of avian type C viruses. The localization of this antigen virus-infected in chick embryo fibroblasts was perinuclear, intracytoplasmic and at the cell surface in the majority of the cells, while it was at the cell surface only in some of the cells. No antigen was found in the nucleus. When chickens were experimentally infected with RAV-1 or a wild-strain avian leukosis virus (of subgroup A), the viral gs antigen was detected in lymphocytes of bursa of Fabricius and the spleen. Distinct specific staining was seen in the medulla of germinal centers in bursas of Fabricius and in the white pulp of the spleen where B lymphocytes are thought to be located. This is consistent with the possibility that B lymphocytes are the target cells in the infection of chickens with avian leukemia viruses.