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 10(6) the particles are capable of producing strong interference in L cells. The rate constant K for thermal inactivation of plaque-forming power is greater than that for interfering power by the factor e(3.8) or about 45 times. At 37 C both properties of the virus decline more slowly and at equal rates. The temperature coefficient of K 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.