Abstract
The effect of antiserum on the interferon (IF) production in macrophages by Newcastle disease virus (NDV) has been studied. Completely neutralized NDV lost its IF-inducing ability, but under-neutralized NDV revealed an enhanced IF-inducing capability. This enhancement of IF production by unneutralized NDV was also observed in antiserum-treated cells. Enhancement phenomena appeared to be based on immunological specificity. Under- neutralized NDV was also adsorbed more rapidly and at a higher rate to normal cells than unneutralized NDV. Unneutralized NDV also adsorbed more efficiently to antiserum-treated cells and to cells derived from immunized mice than to normal cells. The significance of these phenomena is discussed in relation to the induction mechanism of IF in macrophages
