Radioimmunoassay of the Group-specific Antigen in Detection of Avian Leukosis Virus Infection

The major group-specific antigen (gs-a) of avian leukoviruses was detected by radioimmunoassay in extracellular medium of all embryonic ultures prepared from infected chickens. Embryos of birds not carrying an avian]eukosis virus infection and of chickens from a leukosis-free flock could thus clearly be dis-tinguished from infected ones. Release of group-specific antigen into the extra-cellular medium was independent of subgroup or strain of avian leukosis or Rous sarcoma virus. The radioimmunoassay of the group-specific antigen seems to be well suited to complement the COFAL (complement fixation avian leukosis) and RIF (resistance inducing factor) tests in the detection of leukosis virus in infected material