Biomedical subjects

Benoît J Van Den Eynde

Publications and source records attributed to Benoît J Van Den Eynde.

3 recordsLinked to original sources

PubMed2003

Recombinant adenylate cyclase toxin of Bordetella pertussis induces cytotoxic T lymphocyte responses against HLA*0201-restricted melanoma epitopes.

The adenylate cyclase (CyaA) of Bordetella pertussis is able to deliver CD8(+) T cell epitopes into the cytosol of CD11b(+) dendritic cells (DC) following its specific interaction with the alpha(M)beta(2) integrin (CD11b/CD18). This delivery results in intracellular processing and presentation by MHC class I molecules of the CD8(+) T cell epitopes inserted into CyaA. Indeed, we previously showed that CyaA toxins carrying a single cytotoxic T lymphocyte (CTL) epitope can induce efficient protective and therapeutic antitumor immunity in mice. With a view to elaborating cancer immunotherapy in humans using CyaA, we constructed two recombinant CyaA carrying HLA*0201-restricted melanoma epitopes. Here we show that these recombinant CyaA induce strong anti-melanoma CTL responses in HLA*0201 transgenic mice, even after a single i.v. immunization without adjuvant. These responses are long lasting, since they were also detected 5 months after the last injection. Finally, human DC treated with the recombinant CyaA were shown to process and present efficiently the melanoma epitopes to human CTL clones. Altogether, our results demonstrate that tumoral epitopes inserted into CyaA are efficiently processed and presented in association with human MHC molecules. These observations suggest that CyaA is capable of activating antitumoral CTL in humans and highlight the potential of CyaA for use in cancer immunotherapy.

Adenylate Cyclase Toxin↗

PubMed2002

Identification of a new peptide recognized by autologous cytolytic T lymphocytes on a human melanoma.

Melanoma line LG2-MEL expresses several antigens recognized by autologous CTLs. One of them consists of a peptide derived from tyrosinase and presented by HLA-B*3503. We have identified another antigen of LG2-MEL as a peptide presented by HLA-B*4403 and resulting from a point mutation in gene OS-9. This gene is expressed in various normal tissues. It is located on chromosome 12 in the vicinity of the CDK4 locus and is frequently co-amplified with CDK4 in human sarcomas. The mutation, a C-to-T transition, changes a proline residue into a leucine at position 446 of the OS-9 protein. Mutated transcripts were found in all the melanoma sublines of LG2-MEL. None of the 184 tumor samples collected from other cancer patients expressed the mutated transcript, indicating that this is a rare mutational event. Interestingly, some of the melanoma sublines of LG2-MEL have lost the wild-type allele of gene OS-9. Those sublines appear to grow faster in vitro than the sublines that retained the wild-type allele, suggesting that this loss of heterozygosity may favor tumor progression. The mutation we have identified in gene OS-9 might therefore participate in the oncogenic process by affecting the function of this potential tumor-suppressor gene.

Amino Acid Sequence↗

PubMed2002

Tumor-specific shared antigenic peptides recognized by human T cells.

The first tumor-specific shared antigens and the cancer-germline genes that code for these antigens were identified with antitumor cytolytic T lymphocytes obtained from cancer patients. A few HLA class I-restricted antigenic peptides were identified by this 'direct approach'. A large set of additional cancer-germline genes have now been identified by purely genetic approaches or by screening tumor cDNA expression libraries with the serum of cancer patients. As a result, a vast number of sequences are known that can code for tumor-specific shared antigens, but most of the encoded antigenic peptides have not yet been identified. We review here recent 'reverse immunology' approaches for the identification of new antigenic peptides. They are based on in vitro stimulation of naive T cells with dendritic cells that have either been loaded with a cancer-germline protein or that have been transduced with viruses carrying cancer-germline coding sequences. These approaches have led to the identification of many new antigenic peptides presented by class I or class II molecules. We also describe some aspects of the processing and presentation of these antigenic peptides.

Amino Acid Sequence↗