Hepatitis B virus surface protein mutations clustered mainly in CTL immune epitopes in chronic carriers: results of an Iranian nationwide study.
نویسندگان
چکیده
Mutations within the coding region of hepatitis B surface antigen (HBsAg) have been found naturally in chronic carriers. To characterize the mutations of HBsAg from Iranian chronic carriers who were vaccine and/or medication naive. The surface genes from 360 patients were amplified and directly sequenced. The distribution of amino acid substitutions was classified according to different immune epitopes of the surface protein. All isolates belonged to genotype D. 222 (61.6%) of 360 patients contained at least one amino acid substitution. 404 (74.5%) of 542 amino acid changes occurred in different immune epitopes of HBsAg, of which 112 (27.7%) in 32 residues of B-cell epitopes (62 in the 'a' determinant); 111 (27.4%) in 32 residues of T helper; and 197 (48.7%) in 32 residues inside cytotoxic T lymphocyte (CTL) epitopes. One Th (186-197) and two CTL (28-51 and 206-215) epitopes were found to be hotspot motifs for the occurrence of 213 (52.7%) substitutions. 20 stop codons were identified in different epitopes. There was a significant association between amino acid substitutions and anti-HBe seropositivity; however, the correlation between such changes with viral load and ALT levels was not significant. In chronic hepatitis B virus(HBV) carriers, positive selection in particular outside the 'a' determinant appeared to exert influence on the surface proteins. These changes could be immune escape mutations naturally occurring due to the host immune surveillance especially at the T-cell level.
منابع مشابه
Hepatitis B Virus Surface Antigen Variants Clustered Within Immune Epitopes in Chronic Hepatitis B Carriers from Hormozgan Province, South of Iran
Objective(s) The aim of this study was to characterize the hepatitis B virus surface protein genotypes and sequence variations among hepatitis B virus surface antigen (HBsAg) positive chronic patients in Hormozgan province, south of Iran. Materials and Methods A total of 8 patients enrolled in this study. The surface gene was amplified and directly sequenced. Genotypes and nucleotide/amino a...
متن کاملIncidence of Hepatitis B virus Surface Antigen (HBsAg) Mutations in Naïve Treated of Chronic Carriers from Tehran Metropolis, Iran
Abstract Background: Naturally occurred hepatitis B virus (HBV) with surface mutations in a variety of chronic hepatitis B (CHB) patients who have received no vaccine or HBIG bearing substitutions in surface protein, have been reported. Objectives: Current knowledge concerning the prevalence of these naturally occurring surface antigen mutations among Iranian carriers is limited. Patients and M...
متن کاملSurface protein mutations in chronic hepatitis B patients who received hepatitis B vaccine therapy
Objective (s):The aim of this study was to determine the correlation between vaccine therapy and appearance of mutations in hepatitis B surface antigen (HBsAg)-positive chronic hepatitis B virus (HBV) patients. Materials and Methods: 16 patients received the HBV vaccine and another 16 individuals from the control group did not. The surface gene was amplified and directly sequenced from samples...
متن کاملHepatitis B virus surface antigen (HBsAg) mutations are rare but clustered in immune epitopes in chronic carriers from Sistan-Balouchestan Province, Iran.
BACKGROUND Hepatitis B virus (HBV) gene and protein variations have frequently been observed in chronic patients. The aims of this study were to determine the genotypes as well as the patterns of HBsAg variations in chronically-infected patients from the south-eastern part of Iran. METHODS Twenty- one chronic inactive HBV carriers from Sistan-Balouchestan Province (an area with a low prevalen...
متن کاملMutation hot spots in hepatitis B surface antigen in chronic carriers from Khoozestan province, southern of Iran.
Mutations in the human hepatitis B virus (HBV) genome contribute to its escape from host immune surveillance and result in persistent infections. The aim of this study was to characterize the molecular variations of the surface gene and protein in chronically-infected patients from the southern part of Iran. The surface genes from 12 HBV chronic carriers were amplified, sequenced and subsequent...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Journal of viral hepatitis
دوره 20 7 شماره
صفحات -
تاریخ انتشار 2013