Gel filtration and density-gradient sedimentation partially separated the immunoglobulins in sera of atopic persons so that the distribution of antibodies to ragweed and house dust antigens could be studied. Binding of radioiodine-labeled antigens was assayed by the Farr technique and skin-sensitizing antibody by passive transfer. Binding of labeled house dust antigen correlated with the distributions of both IgM and IgG. Binding of ragweed varied. In some sera maximal binding correlated with IgM, in others with IgG, and in still others with both immunoglobulins. In three sera which incidentally contained antibody to BSA, binding appeared to be associated only with IgG. The distribution of binding of ragweed and house dust correlated poorly with the distribution of skin-sensitizing antibody. While a large amount of binding of these antigens by IgG might obscure a small amount of binding by IgA, most of the antibodies which bind ragweed and house dust antigens in vitro are IgM and IgG.

This content is only available via PDF.
You do not currently have access to this content.