OBJECTIVETo use a lectin microarray to study the alteration of glycan affinity profiles of serum glycoproteins during the hepatitis B e antigen (HBeAg) and hepatitis B surface antigen (HBsAg) seroconversion in patients with chronic hepatitis B (CHB) following treatment with antiviral therapy,and to explore its biological significance.

METHODSCHB patients were divided into the following four groups:untreated HBeAg-positive,HBeAg seroconversion after anti-HBV therapy,HBsAg loss after anti-HBV therapy,and healthy individuals (controls).Serum samples were collected from each participant,depleted of high abundance proteins and analyzed by a lectin microarray containing 50 lectins.The lectin-affinity glycan profiles of serum proteins were partially verified by lectin blotting.Between-group differences were analyzed by one-way analysis of variance,and pairwise comparisons were carried out with the Student-Newman-Keuls (SNK) method.

RESULTSThe results from the lectin microarray and lectin blotting assay showed significantly reduced affinity for 16 lectins in the untreated HBeAg-positive group compared to the control group (P less than 0.05);in addition,the specific glycan profiles of the untreated HBeAg-positive group included decreased terminal and core fructose,GalNAc alpha-Thr/Ser (T,Tn-antigen),GalNac alpha,terminal beta1-4,and beta-D galactose,bisecting and/or GlcNAc,mannose and Sia.However,the HBeAg seroconversion after anti-HBV therapy group showed enhanced binding of PSA,MPL and the above-mentioned 16 lectins (P less than 0.05),suggesting that the reduced serum glycoprotein glycan structures returned to normal or slightly higher than healthy levels after the therapy-induced seroconversion.Comparison of the group with HBsAg loss after anti-HBV therapy to the group with HBeAg seroconversion after anti-HBV therapy showed the binding ability of ten lectins (AAL,ACL,HAL,HPL,RCA-I,LEL,STL,PHA-E,NML and PCL) were weakened to near control levels and six lectins (VAL,LCA,GNL,PSA,MPL and JAC) were significantly strengthened (all P less than 0.05). These findings implied that the glycan containing terminal fructose, GalNacalpha, terminal beta1-4 galactose,and bisecting GlcNAc glycan structures dropped to near control levels, while the terminal beta-D-galactose residues and core fructose structure increased significantly.

CONCLUSIONThe glycan structures of serum glycoproteins are closely related to HBeAg and HBsAg seroconversion in CHB patients.It is possible that a special lectin binding glycan involving the terminal beta-D-galactose residues and core fructose may act as sugar markers associated with the disappearance of serum HBsAg during anti-HBV therapy for CHB.