 The purpose of this study is to evaluate the residual allergenicity of the modified ragweed pollen in Ragweed MATA MPL modified pollen allergen tyrosine adsorbate Monophosphoryl Lipid A by skin prick testing. This is done by a comparison of the wheal response after skin prick testing with different concentrations of aqueous native allergen, modified allergen, modified tyrosine adsorbed allergen, and Ragweed MATA MPL. 