Abstract:
Two-dimensional quantal microneutralization tests on foot-and-mouth disease
viruses, in which neutralizing antibody activity was titrated against a serial
range of virus doses, demonstrated a variety of dose-response curves some of
which were rectilinear, others clearly curvilinear. Moreover, in the case of the
non-linear responses obtained with some antisera, the shape of the curve was such
that antibody titres recorded with doses of virus ranging from lCP-lO 5 TCD50
were closely similar. Studies were carried out on the effect of varying the con-
ditions of the test on the shape of the dose-response curve: significant differences
were obtained after treatment of the antiserum-virus mixtures with anti-species
globulin, and when the test was assayed in cells of differing susceptibility to
infection.
