Yolanda Mthembu
Dept. of Clinical Chemistry and Blood Transfusion, Gothenburg University, Sweden
Title: Binding of the gastric pathogen Helicobacter pylori to recombinant mucin fusion proteins carrying Leb, SLex, LacdiNAc and GlcNAcα1,4Gal determinants on O-glycan cores
Biography
Biography: Yolanda Mthembu
Abstract
Helicobacter pylori attach to mucin-glycans with two major attachment prtoteins; the blood group antigen-binding adhesin, BabA, which binds to ABO and Lewis b (Leb) (Fucα1, 2Galβ1,3[Fucα1,4]GlcNAc1-R) and, H type-1 (Fucα1,2Galβ1,3GlcNAc1-R) histo-blood group antigens and, in addition with the sialic acid-binding adhesin, SabA, which binds to sialylated atigens including, sialyl-Lewisx (SLex)(NeuAcα2,3Galβ1,4[Fucα1,3]GlcNAc1-R).
The CHO-K1 cells were genetically engineered to express a mucin-type fusion protein (PSGL-1/mIgG2b) tghat carry Leb and SLex determinants on core 2, core 3 and extended core 1 O-glycans. PSGL-1/mIgG2b that carry LacdiNAc on core 2 and the GlcNAcα1,4Gal1 determinant on core 1 were also expressed by CHO-K1. Immunoblots by lectins and mAbs combend with LC-MS of released glycans were used to identify the O-glycomes of the PSGL-1/mIgG2b proteins. Further, the inhibition of binding of the H. pylori 17875/Leb that express BabA and, the almsot isogenic H. pylori DM that instead express SabA, by the seriues of glyco-engineered PSGL-1/mIgG2b proteins was assessed.
The presence of the Leb, SLex, LacdiNAc and GlcNAcα1,4Gal determinants on PSGL-1/mIgG2b was first confirmed. The H. pylori experiments demonstrated that only PSGL-1/mIgG2b proteins with Leb on core 3 inhibited BabA-mediated binding. On the other hand, the seris of sialylated PSGL-1/mIgG2b proteins all demonstaretd various degrees of inhibition of SabA-mediated binding, suggesting that SabA accepts various substitutyion of sLex for binding, simiar to babA that accets a serios of derivatis of the ABO series (albeit restricted tyo the acto series type 1 core chains).