Another individual (J.R.) whose red blood cells appear to carry a hybrid MNSs sialoglycoprotein.

The serum of J.R. contains anti-Wrb and her red blood cells are of the phenotype Wr(a-b-). Evidence was obtained that suggested that her cells totally lack normal MN and Ss sialoglycoproteins (SGPs), and carry instead an abnormal SGP, which is likely to be a hybrid SGP resembling the MN SGP in its outer portion and the Ss SGP in its inner portion. Although the apparent hybrid SGPs of J.R. and the MiV homozygote are virtually indistinguishable in terms of their electrophoretic mobility (apparent molecular weight 40,000) and staining characteristics, they are not identical. That of J.R. is associated with a weak M and increased S antigen, while that of the MiV homozygote is associated with a very weak N, a greatly exalted s, and the rare antigen, Hil. Like the study on the blood of the MiV homozygote, serologic studies on the red blood cells of J.R. have revealed considerable heterogeneity of what have previously been called the Ena antigen and anti-Ena antibodies.