Immunogenic properties of modified antigen E. III. Effect of repeated injections of modified antigen on immunocompetent cells specific for native antigen

It has been shown that ragweed antigen E loses its major antigenic determinants after denaturation in 8 M urea, but urea denatured (UD) antigen and an α polypeptide chain isolated from the denatured molecules are capable of priming mouse T cells specific for native antigen. Weekly injections of 10μg UD antigen or α chain into antigen E primed animals depressed the ongoing IgE antibody response, whereas injections of the same dose of antigen E failed to depress the antibody response. It was found by adoptive transfer experiments that helper activity of antigen E primed splenic T cells was depressed by the treatment of the donors with either modified antigen or native antigen E. The same treatment of antigen E primed animals depressed the DNA synthetic response of their splenic T cells to antigen E. The treatment of antigen E primed animals with UD antigen resulted in a decrease of antigen E specific IgE B cells and IgG B cells in their spleen, whereas the treatment with native antigen expanded the B cell populations. In view of the results obtained in the mouse, cellular basis for the immunologic effects of hyposensitization treatment is discussed.