Most studies of the immune responses in allergic rhinitis have focused on IgE antibodies to mixtures of allergenic proteins. Based on our previous studies of the major mountain cedar allergen Jun a 1, we sought to describe a broader assessment of the humoral immune responses to a single, dominant allergen, in three groups of allergic subjects, all of whom had similarly exposures to the whole cedar pollen. The major outcomes of this study was that, with the onset of allergic rhinitis symptoms, and after treatment with immunotherapy, serum IgE and IgG (but not IgA) antibodies to Jun a 1 increased. Interestingly, both IgE and IgG4 antibodies to the Jun a 1 allergen were strongly focused on its conformation epitopes. These IgG antibodies to conformationalstructures may be a useful marker of the therapeutic response to immunotherapy.