RELATIVE PLAQUE-FORMING, CELL-INFECTING, AND INTERFERING QUALITIES OF VACCINIA VIRUS.

Galasso, G. J. (University of North Carolina School of Medicine, Chapel Hill), and D. G. Sharp. Relative plaque-forming, cell-infecting, and interfering qualities of vaccinia virus. J. Bacteriol. 88:433-439. 1964.-The growth of vaccinia virus in slant cultures of L cells inoculated with different multiplicities of counted particles suggests a higher incidence of cell infection than can be accounted for by the number of plaque-forming units. From cultures containing antiserum or heated virus to limit the passage of progeny to uninfected cells, the data clearly indicate the ability of all the particles to infect cells even though the plaque titer is only one-tenth of this number. Analogous experiments show that an average of two heat-inactivated (56 C, 45 min) particles induce interference in L cells. There is nothing yet to show whether the few plaque-forming particles are different from the majority or whether they are just statistically fortunate in the complex process of plaque formation.