Biochemical and immunochemical studies of the expression of glycosphingolipid-based ABH and related antigens in normal cells and in plasma

Molecular characterization of a monoclonal murine anti-blood group A antibody

A mouse monoclonal anti-human blood group A antigen (AC12, mu, kappa) has been generated and sequenced in order to analyze the immunoglobulin genes used to generate antibodies with anti-human blood group A specificity. Mice were immunized with human type A RBC. Anti-A producing hybridomas were detected by agglutination against human type A RBC. Total cellular RNA was extracted from hybridomas cells. PCR amplification and sequencing of anti-A heavy and light chain cDNAs were performed. The VH and VK sequences of antibody AC12 were shown to be very homologous to that used by other antibodies recognizing carbohydrates as well as glycoproteins, peptides or haptens constituting self antigens as well as nonself antigens. The VH sequence of antibody AC12 presented important homology with a previously reported monoclonal anti-blood group B antibody. The antibody AC12 also presented homology with the VH and VK sequences of a previously reported human anti-blood group A antibody which contributes additional evidence in favor of a restricted usage of V segments by antibodies directed against red blood antigens.

Presence of glycosyltransferase inhibitors in the sera of patients with long-term surviving ABO incompatible (A2 to O) kidney grafts

In the sera of blood group O recipients with long-term surviving blood group A2 kidney grafts, inhibitors of A-glycosyltransferase (alpha-3-N-acetyl-D-galactosaminyl transferase) have been identified in four out of six patients. The inhibitors seem to be of IgG antibody nature and do not appear until at least 1 year after transplantation. The inhibitors are also active against B-transferase (alpha-3-D-galactosyl transferase) as well as against A-glycosyltransferase of pig origin. The importance of these A-glycosyltransferase inhibitors is not clear. They may have a modifying effect on the antigenic expression of the graft. The immunogenicity of soluble glycosyltransferases is well known and the development of antibodies against them might prevent their enzymatic activity.