Hepatitis B Virus Surface Antigen Variants Clustered Within Immune Epitopes in Chronic Hepatitis B Carriers from Hormozgan Province, South of Iran

• Main Authors: Mehdi Norouzi, Seyed Ali Ghorashi, Behrooz Ataei, Majid Yaran, Reza Malekzadeh, Seyed Moayyed Alavian, Mohammad Ali Judaki, Shiva Ghamari, Alireza Namazi, Ramin Rahimnia, Abolfazl Khedive, Seyed Mohammad Jazayeri
• Format: Article
• Language: English
• Published: Mashhad University of Medical Sciences 2010-09-01
• Series: Iranian Journal of Basic Medical Sciences
• Subjects: HBV genotypes; HBV genotype D; HBV genotype in Iran; HBV immune epitopes
• Online Access: http://www.mums.ac.ir/shares/basic_medical/basicmedjou/89/fall/a9.pdf

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 MethodsA total of 8 patients enrolled in this study. The surface gene was amplified and directly sequenced. Genotypes and nucleotide/amino acid substitutions were identified compared to the sequences obtained from the database.ResultsAll strains belonged to genotype D. Overall 77 “muta¬tions” occurred at 45 nucleotide positions, of them, 44 (57.14%) were silent (no amino acid altering) and 33 (42.86%) were missense (amino acid changing). A number of 24 (80%) out of 30 amino acid changes occurred in different immune epitopes within surface protein, of which, 9 (30%) in B cell epitopes in 7 residues (2 occurred in “a” determinant region); 8 (42.1%) in T helper epitopes in 7 residues and 7 (10%) in 4 residues inside CTL epitopes.ConclusionHepatitis B virus genome containing mutated immune epitopes no longer could be recognized by specific T-cells of the host immune surveillance and did not enhance anti-HBs production. This could led to the progression of chronicity of hepatitis B virus infection.