Polypeptides and major antigens of four new isolates of cytomegalovirus.

Two strains of cytomegalovirus (CMV) from patients with renal transplants and two other strains of CMV from young children were successfully propagated in human diploid cells, MRC5. Analysis by SDS-PAGE of these viruses passaged only 4 to 6 times revealed 21 to 29 polypeptides. The freshly isolated strains differed from reference strains, Ad 169 and Davis, in the number of bands, in the intensity of labeling of each band and also in molecular weight of the polypeptides. Some bands were common to all six strains. Some bands of molecular weight above 105 K were present in some strains and not in others. This was also the case for some bands between 64 and 76 K and two to five bands at low molecular weight between 17 and 22 K were detected. The band at 68 K was the most intensely labeled. Several polypeptides were precipitated by immune sera containing antibodies to CMV (one positive human serum and one guinea pig antiserum to Davis strain). Different bands were observed after precipitation, depending on the antiserum used and the strain of virus. Interstrain differences were found to be associated with antigenic heterogeneity. However, these cannot be correlated as yet with primary infection or reactivation.