Norouzi M, Ghorashi Sa, Abedi F, Nejatizadeh A, Ataei B, Malekzadeh R, Alavian Sm, Judaki Ma, Ghamari S, Namazi A, Rahimnia R, Khedive A, Jazayeri Sm
Iranian National Institute for Genetic Engineering and Biotechnology, Tehran, Iran.
Iran J Public Health. 2012;41(3):104-11. Epub 2012 Mar 31.
Hepatitis B virus (HBV) gene and protein variations are frequently been seen in chronic patients. The aims of study were to determine the genotypes as well as the patterns of variations distribution in chronically-infected patients from the central part of Iran.
The surface gene was amplified, sequenced and subsequently aligned using international and national Iranian database.
All strains belonged to genotype D, subgenotype D1 and subtype ayw2. Of all 62 mutations occurred at 39 nucleotide positions, 31 (50%) were missense (amino acid altering) and 31 (50%) were silent (no amino acid changing). At the amino acid level, 30 substitutions occurred, however, 3 were in positions 122 and 127, corresponded to subtypic determination. 22 (73%) out of 30 amino acid mutations occurred in different immune epitopes within surface protein, of which 12 (54.54%) in B cell epitopes in 10 residues; 5 (45.45%) in T helper epitopes in positions; 5 (22.73%) in inside CTL epitopes in 4 residues.
The distribution of amino acid mutations as well as the ratio between silent and missense nucleotide mutations showed a narrowly focused immune pressure had already been on the surface protein in these patients, led to the emergence of escape mutants in these patients.
乙型肝炎病毒（HBV）基因和蛋白质变异在慢性患者中经常出现。本研究的目的是确定伊朗中部慢性感染患者的基因型以及变异分布模式。
对表面基因进行扩增、测序，随后使用国际和伊朗国家数据库进行比对。
所有菌株均属于D基因型、D1亚基因型和ayw2亚型。在39个核苷酸位置发生的62个突变中，31个（50%）为错义突变（氨基酸改变），31个（50%）为沉默突变（无氨基酸改变）。在氨基酸水平上，发生了30个替换，然而，有3个位于122和127位，与亚型确定相对应。30个氨基酸突变中有22个（73%）发生在表面蛋白内不同的免疫表位中，其中12个（54.54%）在B细胞表位的10个残基中；5个（45.45%）在辅助性T细胞表位的位置中；5个（22.73%）在细胞毒性T淋巴细胞表位内的4个残基中。
氨基酸突变的分布以及沉默和错义核苷酸突变之间的比例表明，这些患者的表面蛋白已经受到了狭窄聚焦的免疫压力，导致这些患者中出现了逃逸突变体。
