Effects of Tween 80 and freon 113 on measles virus.

Measles vaccines were prepared from the same virus fluids by inactivation with formaldehyde or by extraction with ether, ethyl acetate, or Freon 113 in the presence of Tween 80. Tests of antigenic potency, based on antibody levels in guinea pigs, showed that the formaldehyde-inactivated vaccines were more potent than the solvent-inactivated preparations and had the additional advantage of long shelf life. Residual Tween 80 in the solvent-extracted vaccines resulted in marked loss of immunogenic potency without significant loss of hemagglutinating activity. Neither extraction with organic solvents nor exhaustive dialysis efficiently removed Tween 80 from aqueous solutions.