Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0018133 (graft-versus-host disease)
 18,032 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The graft-versus-leukemia effect of allogeneic stem-cell transplantation is believed to be mediated by T-cell recognition of minor histocompatibility antigens on recipient cells. For minor histocompatibility antigens HA-1 and HA-2, normal cell expression is restricted to hemopoietic cells, and boosting the immune response to these antigens may potentiate graft-versus-leukemia effect without accompanying graft-versus-host disease. To increase efficacy, expansion of HA-1- or HA-2-specific CTL before transplantation is desirable. However, primary HA-1- or HA-2-specific CTL expanded in vitro are often of low avidity. An alternative approach is to prime specific CTL responses in vivo by vaccination. Clearly, donor vaccination must be safe and specific. We have developed DNA fusion vaccines able to induce high levels of epitope-specific CTL using linked CD4(+) T-cell help. The vaccines incorporate a domain of tetanus toxin (DOM) fused to a sequence encoding a candidate MHC class I binding peptide. This design generates antitumor CD8(+) T-cell responses and protective immunity in preclinical models. For clinical application, we constructed vaccines encoding HLA-A*0201-restricted peptides from human HA-1 and HA-2, which were fused to DOM, and tested their performance in HLA-A*0201-transgenic mice. Priming induced epitope-specific, IFNgamma-producing CD8(+) T cells with cytotoxic function boosted to high levels with electroporation. Strikingly, these mouse T cells efficiently killed human lymphoblastoid cell lines expressing endogenous HA-1 or HA-2. High avidity is indicated by the independence of cytolysis from CD8/MHC class I interaction. These safe epitope-specific vaccines offer a potential strategy to prime HA-1- or HA-2-specific CTL in transplant donors before adoptive transfer.
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PMID:DNA fusion vaccines induce epitope-specific cytotoxic CD8(+) T cells against human leukemia-associated minor histocompatibility antigens. 1670 72

Non-myeloablative allogeneic stem cell transplantation is an option for the treatment of hematological malignancies as well as solid tumors. We recently proposed a cyclophosphamide-using non-myeloablative cell therapy in which donor lymphocytes infusion (DLI) was carried out after tolerance induction to donor cells. In this study, we tested the possibility that the cyclophosphamide-using cell therapy could be augmented by pre-immunization of donors before DLI. We initially assessed whether or not the cyclophosphamide-using cell therapy could also show antitumor effect against subcutaneously established colon 26 carcinoma. As a tumor antigen-derived peptide for colon 26, we used AH1, an immunodominant H-2Ld-binding peptide derived from the envelope protein (gp70) of an endogenous murine leukemia virus. The cyclophosphamide-using cell therapy with the DLI from donors which were pre-immunized with the AH1 peptide was compared with that from non-immunized mice. The cyclophosphamide-using cell therapy significantly suppressed subcutaneously established colon 26 carcinoma, and the tumor-rejected mice acquired the tumor-specific protective immunity. When combined with the DLI from donors that were immunized with AH1, antitumor effect of the cyclophosphamide-using cell therapy was significantly augmented. The DLI from tumor peptide-immunized donors showed no influence on donor chimerism and bodyweight of the treated mice, indicating no increased risk of graft-versus-host disease. Tumor-specific cytotoxic T lymphocytes could be generated from tumor-rejected mice. Our results indicate that the cyclophosphamide-using non-myeloablative cell therapy with the DLI from tumor peptide-immunized donors is a useful protocol to augment graft-versus-tumor effect without exacerbation of graft-versus-host disease.
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PMID:Allogeneic cell therapy from immunized donors with tumor antigen peptide enhances the antitumor effect after cyclophosphamide-using non-myeloablative allogeneic hematopoietic cell transplantation. 1903 94