ALPHA-2,3-SPECIFIC DESIALYLATION OF HUMAN RED-CELLS - EFFECT ON THE AUTOANTIGENS OF THE PR, SA AND SIA-L1, SIA-B1, SIA-IB1 SERIES

Background and objectives: Pr-1,Pr-2,Pr-3, Pr-M, Sa and Sia-11, -b1, - 1b1 are sialic acid (NeuNAc)-dependent antigens recognized by human co ld agglutinins. Pr and Sa antigens are the O-glycans of glycophorins c ontaining alpha 2,3NeuNAc (to galactose) and/or alpha 2,6NeuNAc (to ga lactosamine). The antigens of the Sia-l1, -b1, -1b1 complex are gangli osides that may carry alpha 2,3NeuNAc (to galactose) and/or alpha 2, 8 NeuNAc (to NeuNAc). We studied the NeuNAc groups involved in the antig ens. Materials and methods: From 74 sera with cold agglutinins against Neu-NAc-dependent antigens, anti-T-free preparations were made and te sted against human red cells, treated with an alpha 2,3-specific recom binant sialidase. Results: Most (51/62) Pr antigens use alpha 2,3NeuNA c, some (8/62) use alpha 2,6NeuNAc and a few (3/62) use both sialyl gr oups as immunodominant components on glycophorins. The immunodominant component of Sa and Sia-l1, -b1, -1b1 determinants was alpha 2,3NeuNAc in all cases. Conclusion: The red cell target structures for cold agg lutinins against NeuNAc-dependent antigens have been identified. We pr opose a Pr nomenclature to reflect this. The binding of anti-Pr to gan gliosides may be the basis for anti-Pr-induced peripheral neuropathy.