N-glycosylation mutations within hepatitis B virus surface major hydrophilic region contribute mostly to immune escape

作者:Yu, De-Min; Li, Xin-Hua; Mom, Vannary; Lu, Zhong-Hua; Liao, Xiang-Wei; Han, Yue; Pichoud, Christian; Gong, Qi-Ming; Zhang, Dong-hua; Zhang, Yan; Deny, Paul; Zoulim, Fabien*; Zhang, Xin-Xin
来源:Journal of Hepatology, 2014, 60(3): 515-522.
DOI:10.1016/j.jhep.2013.11.004

摘要

Background & Aims: HBV immune escape represents a challenge to prevention, diagnosis, and treatment of hepatitis B. Here, we analyzed the molecular and clinical characteristics of HBV immune escape mutants in a Chinese cohort of chronically infected patients. @@@ Methods: Two hundred sixteen patients with HBsAg and anti-HBs were studied, with one hundred eighty-two HBV carriers. without anti-HBs as a control group. Recombinant HBsAg bearing the most frequent N-glycosylation mutations were expressed in CHO and HuH7 cells. After confirming N-glycosylation at the most frequent sites (129 and 131), together with inserted mutations, functional analysis were performed to study antigenicity and secretion capacity. @@@ Results: One hundred twenty-three patients had the wild-type HBs gene sequence, 93 patients (43%) had mutants in the major hydrophilic region (MHR), and 47 of the 93 patients had additional N-glycosylation mutations, which were transmitted horizontally to at least 2 patients, one of whom was efficiently vaccinated. The frequency of N-glycosylation mutation in the case group was much higher than that of the control group (47/216 vs. 1/182). Compared with wild-type HBsAg, HBsAg mutants reacted weakly with anti-HBs using a chemiluminescent microparticle enzyme immunoassay. Native gel analysis of secreted virion in supernatants of transfected HuH7 cells indicated that mutants had better virion enveloping and secretion capacity than wild-type HBV. @@@ Conclusions: Our results suggest that specific HBsAg MHR N-glycosylation mutations are implicated in HBV immune escape in a high endemic area.