Host sex disparity and viral genotype dependence of the glycosylation level of small Hepatitis B surface protein in patients with HBeAg-positive chronic Hepatitis B

Background Hepatitis B surface antigen (HBsAg) consists of six components of large/middle/small HBs proteins (L/M/SHBs) with non-glycosylated (ng)- or glycosylated (g)- isomers at sN146 in their shared S domain. g-SHBs plays a crucial role in hepatitis B virus (HBV) secretion. However, the host and viral factors impacting sN146 status in natural HBV infection remain revealed mainly due to the technical difficulty in quantifying g-SHBs and ng-SHBs in serum samples. Methods To establish a standardized Western blot (WB) assay (WB-HBs) for quantifying the SHBs isomers in serum samples of 328 untreated hepatitis B e antigen (HBeAg)-positive chronic hepatitis B (CHB) patients with genotype B or C HBV infection. The 1.3-mer HBV genotype B or C plasmids were transiently transfected into HepG2 cells for in vitro study. Results The median level of ng-SHBs was significantly higher than that of g-SHBs (N = 328) (2.6 vs. 2.0 log 10 , P < 0.0001). The median g-/ng-SHBs ratio in female patients (N = 75) was significantly higher than that of male patients (N = 253) (0.35 vs. 0.31, P < 0.01) and the median g-/ng-SHBs ratio in genotype C patients (N = 203) was significantly higher than that of the genotype B patients (N = 125) (0.33 vs. 0.29, P < 0.0001). Conclusions Our findings suggest that the g-/ng-SHBs ratio is host-sex-biased and viral genotype dependent in treatment naïve patients with HBeAg-positive chronic hepatitis B, which indicates the glycosylation of SHBs could be regulated by both host and viral factors. The change of ratio may reflect the fitness of HBV in patients, which deserves further investigation in a variety of cohorts such as patients with interferon or nucleos(t)ide analogues treatment.