Table 1.

Wild-type MVs (strains IV, JW, Bcl94, and FV93) induce 10- to 80-fold less IFN-α/β than do the attenuated Edmonston, Moraten, or Vero cell-adapted IV, JW, Bcl, and FV virus strainsa

Virus strainIU of IFN/ml of supernatant
Expt 1Expt 2
NI250120
Edmonston2,0004,000
Moraten5,00010,000
JW120120
IV120250
Bcl94120120
FV93120250
IV-Vero10,0001,250
JW-Vero2,50010,000
Bcl-Vero1,2502,000
FV-Vero1,2502,000
  • a Virus-free supernatants from cells infected with different MV strains were assayed for the biological activity of IFN-α/β. JW and IV are wild-type MV isolates passaged solely on human PBMC, while Bcl94 and FV93 were isolated and passaged on the B958 marmoset cell line. The Edmonston and Moraten MV strains are highly attenuated and were passaged on the monkey Vero cell line. IV-, JW-, Bcl-, and FV-Vero are the wild-type viruses passaged 10 times on Vero cells. NI, noninfected cells.