PLoS One. 2016 Jan 5;11(1):e0145629. doi: 10.1371/journal.pone.0145629. eCollection 2016.

Immunogenicity of HLA Class I and II Double Restricted Influenza A-Derived Peptides.

Pedersen SR1, Christensen JP1, Buus S1, Rasmussen M1, Korsholm KS2, Nielsen M3,4, Claesson MH1.
  • 1Institute of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
  • 2Department of Infectious Disease Immunology, Statens Serum Institute, Copenhagen, Denmark.
  • 3Department of Systems Biology, Center for Biological Sequence Analysis, Technical University of Denmark, Lyngby, Denmark.
  • 4Instituto de Investigaciones Biotecnológicas, Universidad de San Martín, San Martín, Buenos Aires, Argentina.

 

Abstract

The aim of the present study was to identify influenza A-derived peptides which bind to both HLA class I and -II molecules and by immunization lead to both HLA class I and class II restricted immune responses. Eight influenza A-derived 9-11mer peptides with simultaneous binding to both HLA-A*02:01 and HLA-DRB1*01:01 molecules were identified by bioinformatics and biochemical technology. Immunization of transgenic HLA-A*02:01/HLA-DRB1*01:01 mice with four of these double binding peptides gave rise to both HLA class I and class II restricted responses by CD8 and CD4 T cells, respectively, whereas four of the double binding peptides did result in HLA-A*02:01 restricted responses only. According to their cytokine profile, the CD4 T cell responses were of the Th2 type. In influenza infected mice, we were unable to detect natural processing in vivo of the double restricted peptides and in line with this, peptide vaccination did not decrease virus titres in the lungs of intranasally influenza challenged mice. Our data show that HLA class I and class II double binding peptides can be identified by bioinformatics and biochemical technology. By immunization, double binding peptides can give rise to both HLA class I and class I restricted responses, a quality which might be of potential interest for peptide-based vaccine development.

PMID: 26731261

 

Supplement:

In the present work we successfully identified HLA class I/II double binding, strongly immunogenic peptides giving rise to both HLA class I and class II restricted T cell responses. But unfortunately, none of these double restricted peptides were recognized by CD8+ or by CD4+ T lymphocytes in influenza virus infected mice. Why is it so?  Although this question is thoroughly discussed in the paper both from evolutionary and an antigen processing point of view, we missed in our discussion to include probably the most obvious reason for lack of response to influenza-derived peptide reactivity in infected mice: The present work used  reverse immunology (bioinformatics, peptide synthesis, HLA binding assays) in order to detect vaccine relevant, double restricted immunogenic influenza-derived peptides. However, since none of these peptides were recognizes by T cells from influenza infected mice, we suggest that immunogenic peptides discovered by the reverse immunology approach, might only, as far as vaccine-protective peptides are concerned, represent the top of the iceberg. Thus, the occurrence of post-translational peptide modifications such as glycosylation, phosphorylation, methylation, and acetylation of virus-derived peptides might be the rule rather than the exception and explain the lack of protective immunity in mice immunized with native, unmodified HLA class I/II binding peptides in spite of the immunogenic nature of such peptides. This concern may be true for immunogenic peptides identified by reverse immunology for vaccine purposes, whether we are dealing with vaccine-peptides selected to boost anti-infectious or anti-neoplastic immunity.

 

Contact:

Mogens H.Claesson, MSc Professor

Dept of Immunology and Microbiology

Blegdamsvej 3, 2200N Faculty of Health Sciences,University of Copenhagen University Copenhagen, Denmark.

 

 

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