PHYSICAL INTERACTION OF A MURINE LEUKEMIA VIRUS WITH INFLUENZA VIRUS IN VITRO.

Incubated mixtures of PR8 influenza virus and Rauscher leukemia virus retained the egg infectivity and hemagglutinin of the influenza virus and the ability of the Rauscher virus to induce splenomegaly in mice. Density-gradient centrifugation on potassium citrate gradients revealed a new interviral product with an intermediate density as the principal constituent of such mixtures. Chicken erythrocytes adsorbed the Rauscher virus components as well as the influenza virus components of the interviral product from such mixtures at 4 degrees C, whereas the Rauscher virus alone was little adsorbed. The adsorbed interviral product was eluted from the erythrocyte complex after incubation at 37 degrees C.