Effects of Heat on the Infecting, Antibody-Absorbing, and Interfering Powers of Vaccinia Virus

Galasso , G. J. (University of North Carolina School of Medicine, Chapel Hill),and D. G. Sharp . Effects of heat on the infecting, antibody-absorbing, and interfering powers of vaccinia virus. J. Bacteriol.89: 611–616. 1965.—At 56 C the infectivity of vaccinia virus particles is destroyed rapidly, but even when it is reduced by a factor of 106 the particles are capable of producing strong interference in L cells. The rate constantK for thermal inactivation of plaque-forming power is greater than that for interfering power by the factore 3.8 or about 45 times. At 37 C both properties of the virus decline more slowly and at equal rates. The temperature coefficient ofK is discontinuous in the region of 40 C, indicating quite different activation energies for the reactions above and below this critical point. The degradation of interfering power exhibits a similar discontinuity, although less in magnitude, but none has been found in the antibody-reactive power of the virus, which is much more heat resistant.