The Simultaneous Presence of Anti‐I and Anti‐i in Sera¹

Abstract

Summary The specificity of antibodies that detect the antigens I, i, I T , IH (10), IA, IB, iH (iO), and IP 1 , [23, 10, 21, 11, 12, 3, 16, 17, 2, 5, 18, 22, 4, 20, 6, 7] can be established with little difficulty. There remain, however, many cold agglutinins that do not have specificity directed against any one of these antigens; this paper describes studies on 22 such sera, 3 of which react equally with I and i cells (regardless of ABO group) and 19 of which have anti‐I specificity but react with significant strength with i cells as compared to a ‘standard’ anti‐I. Absorption and elution experiments with selected erythrocytes show that all 22 sera contain separable anti‐I and anti‐i.