Demonstration of antibodies in the sera of grass-sensitive persons by the bis-diazotized-benzidine hemagglutination technique

Abstract

The BDB-hemagglutination technique has been adapted for the demonstration of antibodies to grass pollen constituents in the sera of immunized rabbits and grass-sensitive hay fever patients. The grasses used were timothy, June grass, orchard grass, redtop, sweet vernal, and Bermuda grass. The method was shown to be highly sensitive. Titers of the order of 10 4 and 10 2 were obtained with sera of immunized rabbits and of allergic human subjects, respectively. The specificity of the technique was demonstrated by inhibition of the hemagglutination with free soluble pollen constituents. The inhibition of hemagglutination obtained with rabbit antisera was used for establishing antigenic relationships among the various grasses. Timothy, June grass, orchard grass, redtop, and sweet vernal were found to contain common antigens, which were different from those of Bermuda grass and ragweed. The results of Prausnitz-Küstner tests using the cross-neutralization technique with desensitizing doses of each of the five grasses (timothy, June grass, orchard grass, redtop, and Bermuda grass) suggest that redtop grass pollen contains all the allergens common to the other grasses and that timothy, June grass, and orchard grass pollens have a complex and in many respects similar allergenic composition and contain additional allergens to those found in Bermuda grass pollen. Absorption of an allergic serum with adsorbents prepared by coupling grass pollen constituents to polystyrene or erythrocytes resulted in the removal of the hemagglutinating factor(s), which was paralleled by the removal of skin-sensitizing antibodies.