Biomedical subjects

Sylvain Cardinaud

Publications and source records attributed to Sylvain Cardinaud.

7 recordsLinked to original sources

PubMed2006

Immunogenic HLA-B*0702-restricted epitopes derived from human telomerase reverse transcriptase that elicit antitumor cytotoxic T-cell responses.

PURPOSE: The human telomerase reverse transcriptase (hTERT) is considered as a potential target for cancer immunotherapy because it is preferentially expressed in tumor cells. To increase the applicability of hTERT-based immunotherapy, we set out to identify CTL epitopes in hTERT restricted by HLA-B*0702 molecule, a common MHC class I allele. EXPERIMENTAL DESIGN: HLA-B*0702-restricted peptides from hTERT were selected by using a method of epitope prediction and tested for their immunogenicity in human (in vitro) and HLA-B*0702 transgenic mice (in vivo). RESULTS: All the six hTERT peptides that were predicted to bind to HLA-B*0702 molecule were found to induce primary human CTL responses in vitro. The peptide-specific CD8+ CTL lines were tested against various hTERT+ tumor cells. Although differences were observed according to the tumor origin, only three CTL lines specific for p277, p342, and p351 peptides exhibited cytotoxicity against tumor cells in a HLA-B*0702-restricted manner. In addition, this cytotoxicity was inhibited by the addition of peptide-loaded cold target cells and indicated that these epitopes are naturally processed and presented on the tumor cells. Further, in vivo studies using humanized HLA-B*0702 transgenic mice showed that all the candidate peptides were able to induce CTL responses after peptide immunization. Furthermore, vaccination with a plasmid DNA encoding full-length hTERT elicited peptide-specific CTL responses, indicating that these epitopes are efficiently processed in vivo. CONCLUSIONS: Together with previously reported hTERT epitopes, the identification of new CTL epitopes presented by HLA-B*0702 increases the applicability of hTERT-based immunotherapy to treating cancer.

Animals↗

PubMed2005

All the peptides that fit: the beginning, the middle, and the end of the MHC class I antigen-processing pathway.

The end result of the antigen-processing pathway is the display of peptide-bound major histocompatibility complex I (pMHC I) molecules. The pMHC I molecules are expressed on the cell surface where they can be surveyed by CD8(+) T cells for abnormal proteins. MHC I molecules present a large repertoire of peptides that fit perfectly in their binding grooves and represent the otherwise hidden intracellular contents. Many peptides originate as defective ribosomal products in the cytoplasm. In a stepwise manner, the antigen-processing pathway generates and protects the proteolytic intermediates until they yield the final peptides that can fit the MHC I in the endoplasmic reticulum.

Animals↗

PubMed2004

Identification of cryptic MHC I-restricted epitopes encoded by HIV-1 alternative reading frames.

Human immunodeficiency virus (HIV) 1 major histocompatibility complex (MHC) I-restricted epitopes are widely believed to be derived from viral proteins encoded by primary open reading frames. However, the HIV-1 genome contains alternative reading frames (ARFs) potentially encoding small polypeptides. We have identified a panel of epitopes encoded by ARFs within the gag, pol, and env genes. The corresponding epitopic peptides were immunogenic in mice humanized for MHC-I molecules. In addition, cytotoxic T lymphocytes recognizing these epitopes were found in HIV-infected patients. These results reveal the existence of atypical mechanisms of HIV-1 epitope generation. They indicate that the repertoire of epitopes recognized by the cellular anti-HIV-1 immune response is broader than initially thought. This should be taken into account when designing vaccine strategies aimed at activating these responses.

Adult↗

PubMed2004

Use of a lentiviral vector encoding a HCMV-chimeric IE1-pp65 protein for epitope identification in HLA-Transgenic mice and for ex vivo stimulation and expansion of CD8(+) cytotoxic T cells from human peripheral blood cells.

H2-deleted, HLA-A2, or HLA-B7 transgenic mice were used to identify new human cytomegalovirus (HCMV)-derived major histocompatibility complex class I-restricted epitopes. Three different approaches for mice immunization were compared for their ability to induce a cytotoxic CD8(+) T cell (CTL) response: (1). inoculation of infectious HCMV, (2). injection of immunogenic synthetic peptides, and (3). infection with a newly designed HIV-derived central DNA flap positive lentiviral vector encoding the chimeric IE1-pp65 protein (Trip-IE1-pp65). Targets pulsed with either known immunogenic peptides or computer predicted ones were used to characterize CTL. Most of the mice immunized with the pp65 (495-NLVPMVATV-503) immunodominant peptide responded after one injection whereas only two of six mice responded to two successive inoculations with HCMV. Infection of mice with Trip-IE1-pp65 induced activation and expansion of CTL directed against peptides from both pp65 and IE1 and allowed identification of new epitopes. We further demonstrated the high capacity of monocyte-macrophage cells transduced with Trip-IE1-pp65 to activate and expand CTL directed against pp65 from peripheral blood mononuclear cells of HCMV-seropositive donors. Altogether these results suggest that Trip-IE1-pp65 is a powerful construct both to characterize new epitopes in combination with human leukocyte antigen-transgenic mice immunization and to provide an alternative to the use of known infectious and noninfectious approaches to expand effector T cells for adoptive immunotherapy.

Amino Acid Sequence↗

PubMed2003

Dendritic cells generated in the presence of granulocyte-macrophage colony-stimulating factor and IFN-alpha are potent inducers of HIV-specific CD8 T cells.

OBJECTIVE: To investigate the ability of granulocyte-macrophage colony-stimulating factor (GM-CSF) and IFN-alpha to induce the differentiation of peripheral monocytes into dendritic cells (DC) and their ability to trigger an HIV-specific CD8 T-cell response. METHODS: Monocytes isolated from both seronegative controls and HIV-infected individuals were differentiated into DC using GM-CSF with either IL-4 or IFN-alpha for 7 days. We assessed the phenotypic characteristics and IL-12 production by flow cytometry. The ability of DC to trigger CD8 T-cell responses was assessed by means of ELISpot and cytotoxicity assays. In addition, HIV-1-RNA levels were measured in culture supernatants. RESULTS: Compared with control DC generated in the presence of GM-CSF and IL-4, DC generated in the presence of GM-CSF and IFN-alpha expressed higher levels of MHC class I molecules and produced similar or higher levels of IL-12 after CD40 ligation or Staphyloccus aureus Cowan stimulation. GM-CSF/IFN-alpha DC expressed low levels of CD4, CXCR4 and DC-SIGN and did not produce detectable virus during the differentiation period. Pulsed GM-CSF/IFN-alpha DC were found to prime CD8 T cells from HIV-negative controls to exert cytotoxic activity against target cells expressing HIV antigens. HIV peptide-pulsed GM-CSF/IFN-alpha DC promote specific IFN-gamma production by autologous CD8 T cells from HIV-seronegative donors. Furthermore, GM-CSF/IFN-alpha DC from HIV-seropositive patients efficiently present HIV peptides to autologous CD8 T lymphocytes. CONCLUSION: GM-CSF and IFN-alpha allow the generation of DC with high CD8 T-cell stimulating abilities. Therefore, this strategy may represent a novel approach to therapeutic vaccination in HIV disease.

Adoptive Transfer↗

PubMed2003

Role of T cell help and endoplasmic reticulum targeting in protective CTL response against influenza virus.

We report on the induction of primary and long-term memory cytotoxic T lymphocyte (CTL) responses against the nucleoprotein of the influenza virus A/PR8/34 in mice immunized with plasmid DNA targeted to B lymphocytes in the spleen. We found that the magnitude of the CTL response and the size of the pool of memory CTL was greater when the CTL response was induced in presence of T cell help. Interestingly, immunization with a signal sequence-competent transgene was markedly superior to immunization with a transgene lacking the endoplasmic reticulum (ER) targeting sequence, in inducing CTL. We also found a correlation between in vivo protection from lethal virus challenge and (1) the availability of T cell help and (2) ER targeting. Immunization of dendritic cell-deficient mice suggests that B lymphocytes function as antigen-presenting cells in this model of immunization. Collectively, the results suggest that somatic transgene immunization is a conceptually new approach to induce effective anti-viral CTL responses and to assess the parameters critical for long-lasting and protective CTL responses in vivo.

Animals↗

PubMed2003

HLA-B*0702 transgenic, H-2KbDb double-knockout mice: phenotypical and functional characterization in response to influenza virus.

HLA-B*0702 transgenic mice (expressing a chimeric heavy chain with a murine alpha 3 domain: HLA-B7(m alpha 3)) in which the H-2K(b) and H-2D(b) class I-a (Cl I-a(-/-)) genes have been inactivated were compared with H-2K(b)D(b) Cl I-a(+/+) positive controls. Expression of the HLA-B7(m alpha 3) molecules resulted in a 3- to 4-fold increase in peripheral CD8(+) T lymphocyte numbers compared to H-2 Cl I-a(-/-) knockout mice. These cells show a diversified TCR repertoire. Following influenza infection, a significant improvement in HLA-B0702-restricted cytotoxic T lymphocyte (CTL) responses was observed in HLA-B7(m alpha 3), H-2 Cl I-a(-/-) compared to HLA-B7(m alpha 3), H-2 Cl I-a(+/+) mice. The CTL response of infected HLA-B7(m alpha 3), H-2 Cl I-a(-/-) mice was directed against the nucleoprotein (NP) 418-426 epitope in which mutations have accumulated. Whereas all NP 418-426 variant peptides induced a CTL response, cross-reactivity to the variants was affected. These NP mutations could have been selected over time in humans for the virus to escape HLA-B0702-restricted CTL responses since a similar response was seen in humans with, as in mice, altered cross-recognition of the NP 418-426 variants. These animals may prove a suitable model to study HLA-B0702-restricted CTL responses.

Animals↗