Genetic analysis of HAV strains in Tunisia reveals two new antigenic variants
- 85 Downloads
To evaluate the genetic variability of hepatitis A virus (HAV) isolates in Tunisia, serum samples were collected from 99 patients in different Tunisian areas in 2003 containing 92 cases with acute hepatitis, five with severe acute hepatitis and two with fulminant hepatitis. The entire VP1 gene was amplified and sequenced. Sequences were then aligned and a phylogenetic analysis was performed. Additionally, the amino acid (aa) sequence of the VP1 was determined. The analysis of Tunisian HAV isolates revealed that all the isolates were sub-genotype IA with 96.4%–99.8% of identity and showed the emergence of two novel antigenic variants. The Tun31-03 antigenic variant, with a 38 aa deletion containing Met156, Val171, Leu174 and Ala176 and located between 150 and 187 aa of the VP1 protein where neutralization escape mutations, was found. The second antigenic variant, Tun36-03, was isolated from a patient with fulminant hepatitis and presented a substitution of Thr by Pro at position 10 of the VP1 protein. This amino acid is located in a peptide presenting an antigenically reactive epitope of the VP1 protein. This substitution has never been described previously.
KeywordsHepatitis A Virus VP1 protein Amino acid Antigenic variants
This work was supported by the CMCU project, code 04/S0813. We thank all members of virology laboratory CHU Nantes, France, for their technical help. We thank also, Pr Héla Hakim: CHU Habib Bourguiba Sfax, Pr Halim Trabelsi: CHU Farhat Hached Sousse, Pr Noureddine Boujaafar: CHU Sahloul Sousse, Dr Chokri Chouchène: CHU Fattouma Bourguib Monastir, for their helpful assistance in the collection of serum samples. We thank also Pr. Mongia El-Abed: Institut de biotechnologie de Monastir for the article English revision.
- 6.S.M. Lemon, L.H. Ping, in Molecular aspects of picornavirus infection and detection, eds. by B. Stemler, E. Ehrenfeld (American Society of Microbiology, Washington, DC, 1988), p 193Google Scholar
- 8.S.M. Lemon, L.N. Binn, Serum J. Infect. Dis. 148, 1033 (1983)Google Scholar
- 14.J. Felsenstein, PHYLIP: Phylogeny Inference Package, Version 3.5 (University of Washington, Seattle, Washington, 1993)Google Scholar