Survey of antibody against chicken anaemia agent (CAA) by an indirect immunofluorescent antibody technique in breeder flocks in Japan.

Specific immunofluorescent antigens were detected in MDCC-MSB1 cells, a lymphoblastoid cell line from Marek's disease lymphoma, infected with chicken anaemia agent (CAA) by an indirect immunofluorescent antibody (IFA) technique. The large and small granular antigens were first recognised in a small proportion of the cells at 12 hours postinoculation (PI) with CAA. The antigen-positive cells increased gradually thereafter, and they were misshaped and stained irregularly, showing the occurrence of cytopathic effect, after 24 hours PI. Antibody against CAA was examined by an IFA test, in which the MDCC-MSB1 cells infected with CAA were used as a source of antigen, in breeder flocks in Japan. Thirty-nine out of 40 commercial breeder flocks (97.5%) were found to possess the antibody. Of the 381 individual serum samples, 357 (93.7%) were positive. Two positive flocks were found among the 19 specific-pathogen-free flocks examined, which have been maintained at our and six private research laboratories in Japan. The IFA test had the same sensitivity as the neutralisation test (NT) for detecting the antibody against CAA and could be performed more quickly and easily.