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Volume 9 Supplement 2

AIDS Vaccine 2012

  • Poster presentation
  • Open Access

Sequence based typing of HLA-A and B Exons-2 and -3 in a HIV-positive native community with limited HLA diversity from the North of Argentina

  • 1,
  • 1,
  • 1,
  • 1,
  • 2,
  • 2,
  • 3 and
  • 1
Retrovirology20129 (Suppl 2) :P164

https://doi.org/10.1186/1742-4690-9-S2-P164

  • Published:

Keywords

  • Native Community
  • Typing Study
  • Specific Allele
  • Peptide Specificity
  • Restricted Diversity

Background

We previously reported a limited diversity of HLA-class I alleles in two-digits typing studies of HIV-positive native populations from Oran, North of Argentina. In the present study we determine whether the restricted diversity observed at low-resolution reflects also a restricted genetic diversity in HLA peptide groove.

Methods

We studied 65 HIV-positive patients whose HLA-A and -B genes were previously typed by SSOP technique. We set-up a sequence-based typing of the most prevalent alleles in Oran. HLA-A and B were initially PCR-amplified and exons-2 and -3 were sequenced. NCBI-SBT-Interpretation tool was used to confirm the two-digits typing with previous SSOP data. We designed a set of primers specifics for HLAs highly prevalent in Oran to achieve differential PCR-amplification of each allele in heterozygote patients. Phylogenetic analysis was used to assign exons-2 and -3 sequences to a high-resolution HLA group.

Results

Our results show that for HLA-A alleles, 85.1% of A*02 are A*02:01:01:01, 96.7% of A*31 are A*31:01:02 and 92.8% of A*24 are A*24:02:01:01. In the case of A*68, 50% are A*68:01:02 and 31.2% are A*68:17. For HLA-B alleles, B*35 was diverse: B*35:01:01:01 (15.8%), B*35:04:01 (15.8%), B*35:05:01 (21.1%) and B*35:19 (21.1%). 43.8% of B*39-alleles were B*39:05:01 and 25% were B*39:03. 52.9% of B*48-alleles were B*48:01:01 and 35.3% were B*48:03:01. 62.5% of B*51 alleles were B*51:01:01. The mentioned alleles represent the 73.1% of HLA-A genetic diversity and the 45.4% of HLA-B. All the polimorphisms observed lead to non-synonymous changes.

Conclusion

Our results show that two-digits typing of HLA-A usually corresponds with a specific allele in our population. For HLA-B alleles, observed within-subtype diversity was higher. The different protein sequence encoded by exons-2 and -3 may lead to different peptide specificities among alleles from the same HLA-B subtype that would be miss-classified as homogeneous in a low-resolution typing study.

Authors’ Affiliations

(1)
Argentinean Reference Center for AIDS, Buenos Aires, Argentina
(2)
Hospital San Vicente de Paul, San Ramón de la Nueva Oran, Argentina
(3)
Emory Vaccine Center, Atlanta, GA, USA

Copyright

© Dilernia et al; licensee BioMed Central Ltd. 2012

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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