Biomedical subjects

Ferry Ossendorp

Publications and source records attributed to Ferry Ossendorp.

21 records · Page 2Linked to original sources

PubMed2002

Bi-directional allelic recognition of the human minor histocompatibility antigen HB-1 by cytotoxic T lymphocytes.

Human minor histocompatibility antigens (mHag) are target antigens of the graft-versus-leukemia response observed after allogeneic HLA-identical stem cell transplantation. We previously defined the molecular nature of the B cell lineage-specific mHag HB-1. The CTL epitope was identified as the decamer peptide EEKRGSLHVW presented in the context of HLA-B44. The HB-1 antigen is encoded by a locus of yet unknown function on chromosome 5q32. A single nucleotide polymorphism within this locus results in an amino acid change from histidine (H) to tyrosine (Y) at position P8 within the CTL epitope. Based on genomic information, we have developed a PCR-RFLP assay to perform HB-1 typing at the DNA level. We determined that the allelic frequency for the H and Y variant is 0.79 and 0.21, respectively. From these data, we calculated that the expected recipient disparity between HLA-B44-matched sibling pairs for HB-1H is 2.8%, whereas recipient disparity for HB-1Y is expected to be 12.4%. Therefore, we addressed whether the HB-1Y peptide is reciprocally immunogenic. We revealed that both peptide variants bind equally efficient to HLA-B44 molecules and that the H/Y substitution has no influence on formation of epitope precursor peptides by 20 S proteasome-mediated degradation. More directly, CTL recognizing the naturally presented HB-1Y peptide could be generated from a HB-1H homozygous donor using peptide-pulsed dendritic cells. Using a set of synthetic structurally related peptide variants, we found that the H/Y substitution has a major impact on TCR recognition by CTL specific for either of the HB-1 allelic homologues. HB-1 is the first human mHag described that induces bi-directional allogeneic CTL responses that may contribute to a specific graft-versus-leukemia response following allogeneic stem cell transplantation.

Alleles↗

PubMed2002

Effective therapeutic anticancer vaccines based on precision guiding of cytolytic T lymphocytes.

In natural immune responses CD4+ T helper (Th) cells, reactive with peptide antigens presented by major histocompatibility complex (MHC) class II molecules on dendritic cells (DC), can drive the maturation of DC that is required for induction of CD8+ cytolytic T-lymphocyte (CTL) immunity. Proper induction, expansion and maintenance of CTL responses are achieved through delicate interactions between CD4+ T cells, DC and CD8+ T cells involving several ligand-receptor pairs. Th cells to a large extent operate through up-regulation of CD40L, which then interacts with CD40 on DC to cause DC maturation. Subsequent CTL induction by activated DC requires CD80/CD86 on the DC to interact with the CD28 costimulatory receptor on CD8+ T cells. For maintenance and full expansion of CTL, interaction of the DC-expressed 4-1BB ligand with its receptor 4-1BB on CTL is also important. Alternative molecular triggers of DC activation that can support induction of powerful CTL responses include agonistic anti-CD40 antibody or ligands of Toll-like receptors (TLR) such as LPS (TLR4 ligand) or oligodeoxynucleotides containing CpG-motifs (TLR9 ligand). The combination of CpG adjuvant with a 35 amino acid long synthetic peptide comprising both tumor-specific CTL and Th epitopes proved to be a highly effective vaccine formulation capable of inducing therapeutic immunity against human papillomavirus-induced mouse tumors. The recently acquired insights into antigen presentation and costimulatory signals have made possible the development of a new generation of therapeutic anticancer vaccines.

Antigen Presentation↗

PubMedDate not supplied

Effective immunotherapy of cancer in MUC1-transgenic mice using clonal cytotoxic T lymphocytes directed against an immunodominant MUC1 epitope.

The tumor-associated autoantigen MUCI is intensively studied as a potential target for antigen-specific immunotherapy of cancer. Previous reports concerning experiments in preclinical murine tumor models have provided evidence supporting the feasibility of this approach. However, such studies have not been performed with clonal cytotoxic T lymphocyte populations displaying a highly defined MUC1 specificity. The authors demonstrate that the immunodominant MUC1-specific cytotoxic T lymphocyte response in C57BL/6 mice is directed against an H-2Kb-restricted epitope, MUC1(19-27), which is derived from the N-terminal signal sequence of the MUC1 protein. Processing of this epitope was independent of transporter of antigen presentation and proteasome function. Importantly, successful immunotherapy of MUC1-overexpressing tumors in MUC1-transgenic mice was not accompanied by damage to normal somatic MUC1-positive tissues, even when this involved the infusion of large numbers of clonal cytotoxic T lymphocyte that recognized the immunodominant MUC1 epitope. Although the risk for autoimmune pathology is limited, data indicate that immune tolerance in MUC1-positive subjects restricts the breadth of the MUC1-specific cytotoxic T lymphocyte repertoire that is available for recruitment to immunotherapeutic antitumor responses.

ATP Binding Cassette Transporter, Subfamily B, Mem↗