Across the fields of immunology and medicine, the ability to identify and develop therapeutic strategies against primary (i.e. inciting) and secondary (i.e. perpetuating) antigenic proteins has potential to transform basic science and clinical practice. Despite significant in silico and in vitro advancements in the ability to predict antigenic proteins, difficulties in validating individual antigen in vivo immunogenicity dramatically reduces the number of targetable candidates. Here, we describe a novel, quantitative metric, termed the Ratio of Immunogenicity (ROI), which can be utilized to stratify antigens based on their relative immunogenicity (i.e., capacity to stimulate an IgG response). By combining data on the magnitude of the immune response and abundance (i.e. dose) of individual antigens in an in vivo system, a continuum of ROI values can be calculated. This study validates the ROI as a powerful and versatile tool which could be used to guide development of “protective” or predict “pathologic” antigen-specific immune responses