HLA-E surface expression is independent of the availability of HLA class I signal sequence-derived peptides in human tumor cell lines

Giulio Lelio Palmisano, Elisabetta Contardi, Anna Morabito, Vittoria Gargaglione, Giovanni Battista Ferrara, Maria Pia Pistillo

Research output: Contribution to journalArticlepeer-review

Abstract

Human leukocyte antigen (HLA)-E is a nonclassic HLA class I molecule whose expression at the cell surface of tumor cells might allow them to escape T- and natural killer (NK)-cell immune surveillance. In this study, we analyzed HLA-E expression in a panel of human HLA-typed tumor cell lines of different histotypes by flow cytometry with anti-HLA-E monoclonal antibodies and by reverse transcriptase-polymerase chain reaction. Although specific HLA-E transcripts were detected in all cell lines, except in HELA, surface expression was detected at different intensities on seven (23%) of 30 cell lines with higher frequency and intensity among osteosarcoma cell lines. HLA-E-positive tumor cell lines mainly expressed the HLA-A*02 class I allele. Some tumor cell lines demonstrating HLA class I A* or Cw* alleles, which we expected to allow HLA-E surface expression on the basis of reported data on lymphoid cells, instead were HLA-E negative. All tumor cell lines were either tapasin and TAP-1 positive by flow cytometry, except two osteosarcoma cell lines, a finding that suggests an intact assembly machinery for peptide loading. We conclude that the concomitant presence of the appropriate HLA class I alleles with leader sequence-derived peptides and HLA-E heavy chain may not be sufficient to allow HLA-E surface expression in tumor cell lines as opposed to lymphoid cells.

Original languageEnglish
Pages (from-to)1-12
Number of pages12
JournalHuman Immunology
Volume66
Issue number1
DOIs
Publication statusPublished - Jan 2005

Keywords

  • HLA typing
  • HLA-E
  • leader peptides
  • tumors

ASJC Scopus subject areas

  • Immunology
  • Immunology and Allergy

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