CD8+ T cells against multiple tumor-associated antigens in peripheral blood of midgut carcinoid patients.

Autor: Vikman S; Division of Clinical Immunology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden. Sofia.Vikman@klinimm.uu.se, Giandomenico V, Sommaggio R, Oberg K, Essand M, Tötterman TH
Jazyk: angličtina
Zdroj: Cancer immunology, immunotherapy : CII [Cancer Immunol Immunother] 2008 Mar; Vol. 57 (3), pp. 399-409. Date of Electronic Publication: 2007 Aug 24.
DOI: 10.1007/s00262-007-0382-4
Abstrakt: Purpose: The aim of the study was to identify immunogenic HLA-A*0201-binding epitopes derived from a number of classical midgut carcinoid-associated proteins. CD8(+) T cells recognizing tumor-associated antigen (TAA) epitopes are of great interest for the establishment of immunotherapy as a novel treatment for this type of malignancy.
Experimental Design: Midgut carcinoid tumor specimens were microdissected and expression levels of potential TAAs were investigated by quantitative real time PCR. HLA-A*0201-binding motifs were selected using HLA peptide binding prediction algorithms and stabilization of HLA-A*0201 was verified using TAP-deficient T2 cells. Peripheral blood of midgut carcinoid patients was analyzed for peptide epitope recognition and the feasibility of generating peptide-reactive CD8(+) T cells in healthy blood donors was examined by an in vitro stimulation protocol using mature DCs. Activation of patient and healthy donor CD8(+) T cells was analyzed by intracellular flow cytometry staining of interferon gamma.
Results: Chromogranin A (CGA), tryptophan hydroxylase 1 (TPH-1), vesicular monoamine transporter 1 (VMAT-1), caudal type homeobox transcription factor 2 (CDX-2), and islet autoantigen 2 (IA-2) are properly expressed by midgut carcinoid tumor cells, with CGA mRNA expressed to greatest level. Midgut carcinoid patients have increased frequencies of peripheral blood CD8(+) T cells recognizing a pool of HLA-A*0201 peptides derived from these proteins compared to healthy age-matched individuals. Activated peptide-specific CD8(+) T cells could also be generated in healthy blood donors by in vitro stimulation.
Conclusion: We have identified a number of immunogenic midgut carcinoid-associated peptide epitopes recognized by CD8(+) T cells. We show that midgut carcinoid patients display immune recognition of their tumors. Memory CD8(+) T cells in patient blood are of great interest when pursuing an immunotherapeutic treatment strategy.
Databáze: MEDLINE
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