Mutation analysis of T-cell and B-cell epitopes derived from HBV PreS-S protein in HBsAb positive occult hepatitis B virus infection
10.3760/cma.j.cn112866-20240530-00090
- VernacularTitle:HBsAb阳性隐匿性乙型肝炎病毒T细胞及B细胞表位变异分析
- Author:
Yan GUO
1
;
Yuanyuan JING
;
Jin LI
;
Hanshi GONG
;
Yong DUAN
;
Yan LI
;
Wenjuan ZHANG
Author Information
1. 陕西省血液中心，西安 710061
- Keywords:
Occult hepatitis B virus infection;
PreS-S region;
Cell epitope mutation
- From:
Chinese Journal of Experimental and Clinical Virology
2024;38(5):506-512
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To analyze the mutation of T-cell and B-cell epitopes derived from HBV PreS-S protein in occult hepatitis B virus (OHBV) and investigate the biological mechanisms of occult hepatitis B virus infection (OBI) and HBsAb positive OBI.Methods:The PreS-S region of OBI samples were amplified by nested PCR, the products were sequenced and HBV genotypes were determined. The mutations of T-cell and B-cell epitopes derived from HBV PreS-S protein were analyzed and compared among groups of HBV genotypes and the presence of HBsAb. The affinity of the high frequency of T-cell epitope substitutions were analyzed by SYF PEITHI, the changes of antigenic characteristics of high frequency of B-cell epitope substitutions were analyzed by Ab Designer, Expasy ProtParam tool, Epitope Prediction and Analysis Tools.Results:The PreS-S region of HBV was amplified in 21 samples, including 4 HBsAb+ OBI B, 6 HBsAb-OBI B, 6 HBsAb+ OBI C, 5 HBsAb-OBI C. The mutation rates in PreS-S region of OBI were significantly higher than wild type HBV strains(OBI Bvs. WT B: 2.64%: 0.66%, P<0.001; OBI Cvs. WT C: 3.67%: 1.19%, P<0.001). The mutation rates of the immunoreactive area were significantly higher than non-immunoreactive area in OBI (OBI B: 3.57%: 1.86%, P=0.005; OBI C: 4.78%: 2.65%, P<0.001). The mutation rates of the immunoreactive and non-immunoreactive area in OBI C were higher than OBI B, but there was no statistically significant difference (immunoreactive area: 4.78%: 3.57%, P=0.107; non-immunoreactive area: 2.65%: 1.86%, P=0.142). The mutation rates of T-cell and B-cell epitopes of HBsAb-OBI were higher than HBsAb+ OBI, although there was no significant difference (HBsAb-OBI Bvs. HBsAb+ OBI B: 4.17∶3.01, P=0.303; HBsAb-OBI Cvs. HBsAb+ OBI C: 5.65∶4.26, P=0.207). The affinity analysis of 4 high frequency T-cell epitope substitutions, including T47A/K, S174N, L175S, V177A, showed that the changes of affinity of most mutation sites were not obvious; the antigenicity analysis of 3 high frequency B-cell epitope substitutions, including G73S, K122R, I126M/T, did not show noticeable changes and the hydrophilicity, surface accessibility of some mutation sites were even better than wild strain. Conclusions:The mutation rates in PreS-S region of OBI were significantly higher than wild type HBV strains. The mutation rates of the immunoreactive area were higher than non-immunoreactive area in OBI. The variant activity of OBI C was higher than OBI B. The mutations of OBI might occur randomly and were not selected by antibody pressure. Single epitope and multi-epitopes combinational mutations might be a reason for OBI.
