Detection of non-precipitating antibodies in sera of individuals allergic to ragweed pollen by an in vitro method.

A hemagglutination test capable of demonstrating antibodies in sera of ragweed-sensitive individuals has been described in detail. This test involves coupling of the antigen to rabbit erythrocytes via stable azo bonds. The antigen-coated cells are then suspended in the serum which is suspected to contain the homologous antibodies.

The localization of skin-sensitizing antibody in the sera of ragweed-sensitive individuals by electrophoresis.

Starch electrophoresis was used to separate allergic sera into electrophoretically distinct albumin, alpha-, beta-, and gamma-globulin fractions. The identity of the various fractions was established by free and paper electrophoresis. The gamma-globulin fractions were also characterized by ultracentrifugation.