Beschreibung:
<jats:title>Summary</jats:title>
<jats:p>The quantal assay system of influenza virus multiplying in surviving bits of the allantois is shown to be suited to the quantitative study of neutralization. Complications, such as bias due to the continued presence of serum or to shielding of infectible cells from the action of antibody, are not evident in standard tests.</jats:p>
<jats:p>It is demonstrated that a) the final equilibrium is the same whether approached from the side of virus or antibody excess; b) changes in test volume lead to predictable shifts of equilibrium; c) the effect of noninfective virus particles is compatible only with random reversible combination of antibody molecules with antigenic sites. On this evidence a model of neutralization based on the law of mass action is accepted as working hypothesis.</jats:p>
<jats:p>The assay is not sensitive to minor inhomogeneity of the reagents, and thus not suited to the study of heterogenity either of the virus or of the antibody population.</jats:p>