Blood group A pentasaccharide (A-Pentasaccharide), an oligosaccharide in urine, can inhibit the binding of anti-A antibody to blood group A substance[1].
References
[1] Sabharwal H, et al. Blood group specific oligosaccharides from faeces of a blood group A breast-fed infant. Mol Immunol. 1984 Nov;21(11):1105-12. DOI:10.1016/0161-5890(84)90121-4
