Anti-HBV PreS2 Monoclonal antibody, Clone J.23

Many variations exist in the first 39 nucleotides of the preS2 (pre-S2: 1-39) region of the HBV genome. Based on the similarities of their coding amino acid sequences to those of prototype HBV, they were classified into 3 different types, adr-preS2, adw-preS2 and ayw-preS2. To clarify the meaning of these variabilities in the preS2 region, we studied the HLA class I phenotype of chronic hepatitis B patients having high levels of serum ALT. Our results indicated that in 12 of 14 chronic hepatitis patients infected with HBV type adr-preS2 had HLA-A24 phenotype whereas all of 7 patients infected with either adw- or ayw-preS2 HBV had HLA-A2 phenotype. This strong association between HLA class I phenotype and certain preS2 types of HBV infection was found only in patients with high serum ALT levels but not in patients with almost normal levels of serum ALT. Our results therefore suggest that in the generation of chronic hepatitis B a suitable combination between a fragment of preS2 antigen and HLA class I antigens of the infected host, such as adr-preS2 with HLA-A24 and either adw- or ayw-preS2 with HLA-A2, might be required.

Hepatitis B virus (HBV) intrauterine infection remains to be an important cause for a large number of persistent hepatitis B surface antigen (HBsAg) positive carriers in areas with a high HBV prevalence, particularly in China and Southeast Asia. In this study, the possible association between the HBV genomic heterogeneity and intrauterine infection was investigated by comparing the quasi species isolated from eight pairs of HBsAg-positive mothers and their neonates, who were infected intrauterinely with HBV, with clones from eight HBsAg-positive mothers whose neonates were not infected with HBV. The proportion of clones with specific mutations was compared among different Subject groups, and phylogenetic analysis was performed to evaluate the significance of specific mutations. It was observed that the core promoter with conserved major functional regions and conserved hepatitis B e antigen (HBeAg) might be beneficial to HBV maternal-fetal transmission. Particularly, A1762T/G1764A mutations seemed to be disadvantageous for fetal infection. It was also shown that amino acid substitutions located in the immune epitopes of HBsAg were strongly associated with intrauterine HBV transmission. The clones with mutations such as amino acid P110S in preS1 region, P36L in preS2 region and C107R in S region might infect fetuses more readily. In addition, positively selected site analysis confirmed the above results. (C) 2009 Elsevier Inc. All rights reserved.