Publications & Reports

Identification of Native and Post-Translationally Modified HLA-B*57:01-Restricted HIV Envelope Derived Epitopes Using Immunoproteomics.

Ramarathinam SH, Gras S, Alcantara S, Yeung AWS, Mifsud NA, Sonza S, Illing PT, Glaros EN, Center RJ, Thomas S, Kent SJ, Ternette N, Purcell DFJ, Rossjohn J, Purcell AW
Infection and Immunity Program, Biomedicine Discovery Institute & Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia.

Abstract

The recognition of pathogen-derived peptides by T lymphocytes is the cornerstone of adaptive immunity, whereby intracellular antigens are degraded in the cytosol and short peptides assemble with class I human leukocyte antigen (HLA) molecules in the endoplasmic reticulum (ER). These peptide-HLA complexes egress to the cell surface and are scrutinized by cytotoxic CD8+ T-cells leading to the eradication of the infected cell. Here we identify naturally presented HLA-B57:01 bound peptides derived from the envelope protein of the human immunodeficiency virus (HIVenv). HIVenv peptides were present at a very small percentage of the overall HLA-B57:01 peptidome (<0.1%) and both native and post-translationally modified forms of two distinct HIV peptides were identified. Notably, a peptide bearing a natively encoded C-terminal tryptophan residue was also present in a modified form containing a kynurenine residue. Kynurenine is a major product of tryptophan catabolism and is abundant during inflammation and infection. We examined the binding of these peptides at a molecular level and examine their immunogenicity in preliminary functional studies. Modest immune responses were observed to the modified HIVenv peptide, highlighting a potential role for kynurenine-modified peptides in the immune response to HIV and other viral infections. This article is protected by copyright. All rights reserved.

Publication

  • Journal: Proteomics
  • Published: 13/02/2018
  • Volume: 18
  • Issue: 12
  • Pagination: e1700253

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