Human T cell responses to endogenously presented HLA-A\*0201 restricted peptides of Simian virus 40 large T antigen

Our plain-English summary of Human T cell responses to endogenously presented HLA-A*0201 restricted peptides of Simian virus 40 large T antigen, by M.P. Velders, M.F. Macedo, M. Provenzano, et al (Journal of Cellular Biochemistry, 2001).

The study

• Authors: M.P. Velders, M.F. Macedo, M. Provenzano, A.G. Elmishad, H.G. Holzhütter, M. Carbone, W.M. Kast
• Journal: Journal of Cellular Biochemistry
• Published: 2001;82(1):155-62
• Cited by: 10 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Presence of the simian virus 40 (SV40) has recently been demonstrated in a relatively high percentage of human mesotheliomas and it is associated with the development of these malignancies in pleural cavities. Therefore, we have initiated a study to identify candidate peptides presented by the human HLA-A*0201 molecule for vaccination approaches against SV40 and monitoring of SV40 directed human immune responses. Initial screening of SV40 large T (Tag) domains required for transformation of cells for HLA-A*0201 binding motifs revealed ten possible binding peptides. Screening of these candidate peptides showed that seven of the ten peptides could bind and stabilize HLA-A*0201 molecules. In an in vitro immunization assay the two peptides with the highest binding affinity for HLA-A*0201, Tag aa 396-405 and aa 577-585, were tested for their ability to induce peptide specific cytotoxic T cells in two healthy donors. One donor developed cytotoxic T cells against Tag aa 396-405 and in T cell cultures of both donors Tag aa 577-585 specific T cells were initiated. The T cells against Tag aa 577-585 not only recognized and killed peptide pulsed cells, but, most importantly, SV40 transformed human mesothelial cells. This is the first demonstration of the induction of SV40 specific human cytotoxic T lymphocytes that recognize endogenously processed peptides from SV40. This peptide identification study opens the possibility to investigate immune responses against SV40 in mesothelioma patients and in individuals exposed to SV40.

Copyright 2001 Wiley-Liss, Inc.

In plain English

This laboratory study searched the simian virus 40 (SV40) large T antigen (Tag) for short peptides that could be presented by the human HLA-A*0201 molecule. Using a computer prediction program, the authors screened only the Tag regions considered indispensable for SV40 transformation (the J domain, the pRb binding domain, and two p53 binding domains) and found ten candidate peptides, nine of them in the p53 binding domains and none in the pRb binding domain. Seven of the ten bound and stabilised HLA-A*0201 on T2 cells. The two best binders, Tag aa 396-405 and aa 577-585, were used to stimulate CD8 cells from two healthy HLA-A*0201 positive donors with peptide-loaded dendritic cells. Donor A had 3/48, 33/48 and 13/48 positive cultures and donor B 21/48, 33/48 and 41/48 for Tag 396-405, Tag 577-585 and a control HBV peptide. T cells against Tag aa 577-585 from both donors killed SV40 and EJ-ras transformed human mesothelial cells (MEJT10); T cells against Tag aa 396-405 did not. The authors concluded that at least two peptides are immunogenic in humans and at least one is endogenously processed.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: In vitro laboratory immunology study: computer-based epitope prediction, peptide binding assay, in vitro immunization of human T cells, and chromium release cytotoxicity assays
• Who was studied: CD8 cells from peripheral blood lymphocytes of two healthy HLA-A*0201 positive blood donors (donor A and donor B), plus human cell lines (MEJT10 SV40/EJ-ras transformed mesothelial cells, JY, T2, K562)
• Exposure: Synthetic peptides derived from SV40 large T antigen domains required for transformation (J domain, pRb binding domain aa 91-120, p53 binding domains aa 251-470 and aa 521-640); not an asbestos exposure study
• Main results:
  • Ten candidate HLA-A*0201 binding peptides were predicted; nine came from the p53 binding regions and none from the pRb binding domain
  • Seven of the ten predicted peptides actually bound HLA-A*0201 in the T2 assay (binding defined as fluorescence index greater than 1)
  • Cultures scored positive for peptide-specific lysis: donor A 3/48 (Tag 396-405), 33/48 (Tag 577-585), 13/48 (HBV 18-27); donor B 21/48, 33/48 and 41/48 respectively
  • In the pooled restimulated cultures, donor B (not donor A) induced CTLs against Tag aa 396-405, while both donors induced responses against Tag aa 577-585
  • T cells specific for Tag aa 577-585 killed the SV40 and EJ-ras transformed human mesothelial cell line MEJT10; T cells specific for Tag aa 396-405 did not
  • The proteasomal cleavage algorithm did not predict generation of Tag 577-585, the peptide found to be naturally processed
• The authors' conclusion: The authors concluded that the study identified HLA-A*0201 binding SV40 Tag peptides recognised by the immune system, with at least two immunogenic in humans and at least one endogenously processed by SV40 transformed cells, providing tools for evaluating T cell responses after SV40 directed vaccination
• Limitations the authors state:
  • Restricting the search to transformation-related Tag regions risked missing immunogenic peptides elsewhere in the protein
  • The binding prediction program is limited and may not rank potential binding peptides correctly

Topics

Medical terms in this study, explained in our Lexicon: SV40, Mesothelioma, Mesothelial Cells.

Related studies

• Simian virus-40 large-T antigen binds p53 in human mesotheliomas — M. Carbone, P. Rizzo, et al. (1997)
• The retinoblastoma gene family pRb/p105, p107, pRb2/p130 and simian virus-40 large T-antigen in human mesotheliomas — A. De Luca, A. Baldi, et al. (1997)
• Human mesotheliomas contain the simian virus-40 regulatory region and large tumor antigen DNA sequences — H.I. Pass, J.S. Donington, et al. (1998)
• Simian virus 40 large T antigen (SV40LTAg) primer specific DNA amplification in human pleural mesothelioma tissue — C. Pepper, B. Jasani, et al. (1996)
• SV40 large T-antigen and human pleural mesothelioma. Screening by polymerase chain reaction and tyramine-amplified immunohistochemistry — K. Dhaene, A. Verhulst, et al. (1999)
• Simian virus (SV) 40 like sequences in cell lines and tumour biopsies from Australian malignant mesotheliomas — B.R. McLaren, T. Haenel, et al. (2000)

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