Reconstitution of the masking effect of sialic acid groups on sialidase-treated erythrocytes by the action of sialyltransferases.

Glutardialdehyde-fixed or native rat erythrocytes were partially desialylated by the action of Vibrio cholerae sialidase, resulting in the binding of these cells to homologous peritoneal macrophages. Resialylation of these erythrocytes by purified alpha-(2----3)- or alpha-(2----6)-sialyltransferases with CMP-N-acetylneuraminic acid led to the incorporation of 60-80% of the enzymically released sialic acid. Binding of the resialylated erythrocytes to peritoneal macrophages was reduced when compared with corresponding, partially desialylated erythrocytes. Thus, the amount of transferred sialic acid was sufficient to demonstrate reconstitution of the masking effect of sialic acids.