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Immune evasion mechanisms in colorectal cancer liver metastasis patients vaccinated with TroVax (MVA-5T4)

Elkord, E, Dangoor, A, Burt, D and Southgate, T 2009, 'Immune evasion mechanisms in colorectal cancer liver metastasis patients vaccinated with TroVax (MVA-5T4) ' , Cancer Immunology, Immunotherapy, 58 (10) , pp. 1657-1667.

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    Abstract

    We have recently reported the results of a phase II trial in which two TroVax [modified vaccinia ankara (MVA) encoding the tumour antigen 5T4] vaccinations were given to patients both pre- and post-surgical resection of liver metastases secondary to colorectal cancer (CRC). 5T4-specific cellular responses were assessed at the entry and 2 weeks after each vaccination by proliferation of fresh lymphocytes and ELISA for antibody responses; 18 from the 19 CRC patients mounted a 5T4-specific cellular and/or humoral response. Here, we present a comparison of individual and between patient responses over the course of the treatments using cryopreserved peripheral blood mononuclear cells (PBMC) samples from the baseline until after the fourth vaccination at 14 weeks. Assays used were proliferation assay with 5T4-Fc fusion protein, overlapping 32mer 5T4 peptides, MVA-LacZ and MVA-5T4 infected autologous monocytes. Responses to 5T4 protein or one or more peptide pools were pre-existing in 12/20 patients and subsequently 10 and 12 patients showed boosted and/or de novo responses, respectively. Cumulatively, 13/20 patients showed proliferative responses by week 14. We also assessed the levels of systemic T regulatory cells, plasma cytokine levels, phenotype of tumour-infiltrating lymphocytes including T regulatory cells and tumour HLA class I loss of expression. More than half of the patients showed phenotypes consistent with relative immune suppression and/or escape highlighting the complexity of positive and negative factors challenging any simple correlation with clinical outcome.

    Item Type: Article
    Themes: Health and Wellbeing
    Schools: Colleges and Schools > College of Science & Technology > School of Environment and Life Sciences
    Journal or Publication Title: Cancer Immunology, Immunotherapy
    Publisher: Springer Verlag
    Refereed: Yes
    ISSN: 0340-7004
    Depositing User: E Elkord
    Date Deposited: 12 Oct 2011 11:58
    Last Modified: 07 Jul 2014 12:27
    URI: http://usir.salford.ac.uk/id/eprint/18238

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