CELLS infected with infectious bronchitis (IB) virus in tissue cultures of chick or chick embryo kidney have been described as showing shrinkage, vacuolation and detachment from the monolayer1–4. When the immuno-fluorescent technique was used, the growth of IB virus in chick embryo kidney cells, first in the nucleus and later in the cytoplasma, was described5. A study was undertaken to obtain additional information about the location of IB virus, and to determine the type of viral nucleoprotein to assist in classification of the virus6.