Production of Allo‐Anti‐Ena by an Individual Whose Red Blood Cells Carry Some Ena Antigen

Abstract
An individual whose red blood cells [RBC] appear to carry a hybrid MNSs sialoglycoprotein (SGP) was described. The MN-derived portion of that SGP carries at least 2 determinants defined by some examples of antibodies that were called anti-Ena. The RBC lack a different determinant that is defined by other examples of anti-Ena. This individual has now formed an anti-Ena antibody that reacts with the portion of Ena that her RBC lack, but not with the Ena determinants that are carried on MN SGP. Whether the portion of Ena that the RBC lack and that the antibody defines is MN SGP-borne is not clear. Apparently the terms En and anti-Ena, as previously used, described heterogeneous groups of antigens and antibodies.