Importantly, for antibody status determination by use of only two monoclonal conjugates, the IgG3 plus IgA1 combination may have an advantage for detection of recent chlamydial infections (37, 56, 57), while the IgG1 plus IgG3 combination is optimal for detection of total antibody status. The gene discussed is IGHG3; the disease is chlamydia trachomatis infectious disease.