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Stanley R Riddell

Publications and source records attributed to Stanley R Riddell.

At least 19 recordsLinked to original sources
PubMed2025

Quantifying HLA transcripts by genotype in chimeric mixtures at single-cell resolution.

Gene products from the highly variable major histocompatibility locus, including HLA, are essential for self-recognition and immune surveillance of malignancy. Following allogeneic hematopoietic cell transplantation (alloHCT), genetic and epigenetic alterations in HLA can drive disease recurrence, making precise HLA assessment critical for determining future therapy. However, current methods lack the sensitivity to quantify HLA transcripts at the single-cell level, limiting their clinical utility. We introduce scrHLA-typing, a novel technique that accurately identifies and quantifies HLA transcripts in single cells using long-read sequencing. When applied to samples from patients with post-transplant relapse, scrHLA-typing successfully detected HLA allele-specific expression, across a range of levels of donor-recipient chimerism, at clinically actionable levels. By characterizing allele expression in residual leukemia cells, our assay identified differences in expression patterns among patients. This capability highlights scrHLA-typing's potential to improve risk stratification and guide the selection of appropriate salvage therapies, enhancing personalized treatment strategies after relapse.

Journal Article↗
PubMed2007

Immunity to adeno-associated virus-mediated gene transfer in a random-bred canine model of Duchenne muscular dystrophy.

Recombinant adeno-associated virus (rAAV)-mediated gene transfer has shown promise for treating diseases in various animal models including the mdx mouse model of Duchenne muscular dystrophy (DMD). In many cases, however, preclinical studies in inbred mice have not successfully predicted human clinical responses. To assess the potential clinical utility of treating human DMD patients by AAV-mediated gene delivery, we performed a series of direct intramuscular injections in random-bred wild-type dogs. AAV serotypes 2 and 6 carrying different promoter-transgene cassettes were produced as previously described for murine studies and administered intramuscularly. The injection sites were biopsied at various time points and analyzed for transgene expression and immunohistochemical analysis. In contrast to the generally nonimmunogenic nature of these vectors in murine studies, both AAV2 and AAV6 vectors elicited robust cellular immune responses regardless of the transgene expressed, the cellular specificity of the promoter, and the muscle type injected. Viral purification by various methods did not diminish T cell-mediated infiltration. Our data indicate that AAV2 and AAV6 capsid proteins can elicit primary cellular immune responses when injected into the skeletal muscle of random-bred dogs, and suggest the possibility of cellular immunity to AAV vectors in humans.

Animals↗
PubMed2006

Redox regulation facilitates optimal peptide selection by MHC class I during antigen processing.

Activated CD8(+) T cells discriminate infected and tumor cells from normal self by recognizing MHC class I-bound peptides on the surface of antigen-presenting cells. The mechanism by which MHC class I molecules select optimal peptides against a background of prevailing suboptimal peptides and in a considerably proteolytic ER environment remained unknown. Here, we identify protein disulfide isomerase (PDI), an enzyme critical to the formation of correct disulfide bonds in proteins, as a component of the peptide-loading complex. We show that PDI stabilizes a peptide-receptive site by regulating the oxidation state of the disulfide bond in the MHC peptide-binding groove, a function that is essential for selecting optimal peptides. Furthermore, we demonstrate that human cytomegalovirus US3 protein inhibits CD8(+) T cell recognition by mediating PDI degradation, verifying the functional relevance of PDI-catalyzed peptide editing in controlling intracellular pathogens. These results establish a link between thiol-based redox regulation and antigen processing.

Antigen Presentation↗
PubMed2006

An antigen produced by splicing of noncontiguous peptides in the reverse order.

CD8-positive T lymphocytes recognize peptides that are usually derived from the degradation of cellular proteins and are presented by class I molecules of the major histocompatibility complex. Here we describe a human minor histocompatibility antigen created by a polymorphism in the SP110 nuclear phosphoprotein gene. The antigenic peptide comprises two noncontiguous SP110 peptide segments spliced together in reverse order to that in which they occur in the predicted SP110 protein. The antigenic peptide could be produced in vitro by incubation of precursor peptides with highly purified 20S proteasomes. Cutting and splicing probably occur within the proteasome by transpeptidation.

Alleles↗
PubMed2006

Recognition of breast cancer cells by CD8+ cytotoxic T-cell clones specific for NY-BR-1.

Immunotherapy for breast cancer using cytotoxic T cells (CTL) is hindered by the lack of well-characterized breast cancer antigens that are expressed in most breast tumor cells and recognized by CD8+ CTL. A recently described breast tissue differentiation antigen, NY-BR-1, is expressed in >80% breast tumors and elicits a humoral response in a subset of breast cancer patients. To identify potential NY-BR-1 epitopes that are recognized by CTL, CD8+ T cells were stimulated in vitro with autologous dendritic cells pulsed with NY-BR-1 peptides that were predicted to bind to HLA-A2. In multiple normal female donors and breast cancer patients, specific CD8+ CTL responses were detected by enzyme-linked immunospot assay against several NY-BR-1 peptides after two cycles of stimulation. CD8+ CTL clones against three NY-BR-1 epitopes were isolated and recognized peptide-pulsed target cells with high avidity. T-cell clones specific for one of the NY-BR-1 epitopes (p904) also recognized breast tumor cells expressing NY-BR-1, NY-BR-1(-) cells transfected with a cDNA encoding the NY-BR-1 protein, and autologous dendritic cells pulsed with opsonized NY-BR-1+ breast tumor cells. Taken together, these results show that the p904 epitope derived from NY-BR-1 is efficiently processed and presented endogenously and identify NY-BR-1 as a promising target for T-cell-based immunotherapy for breast cancer.

Antigen Presentation↗
PubMed2006

The PANE1 gene encodes a novel human minor histocompatibility antigen that is selectively expressed in B-lymphoid cells and B-CLL.

Minor histocompatibility antigens (mHAg's) are peptides encoded by polymorphic genes that are presented by major histocompatibility complex (MHC) molecules and recognized by T cells in recipients of allogeneic hematopoietic cell transplants. Here we report that an alternative transcript of the proliferation-associated nuclear element 1 (PANE1) gene encodes a novel human leukocyte antigen (HLA)-A(*)0301-restricted mHAg that is selectively expressed in B-lymphoid cells. The antigenic peptide is entirely encoded within a unique exon not present in other PANE1 transcripts. Sequencing of PANE1 alleles in mHAg-positive and mHAg-negative cells demonstrates that differential T-cell recognition is due to a single nucleotide polymorphism within the variant exon that replaces an arginine codon with a translation termination codon. The PANE1 transcript that encodes the mHAg is expressed at high levels in resting CD19(+) B cells and B-lineage chronic lymphocytic leukemia (B-CLL) cells, and at significantly lower levels in activated B cells. Activation of B-CLL cells through CD40 ligand (CD40L) stimulation decreases expression of the mHAg-encoding PANE1 transcript and reciprocally increases expression of PANE1 transcripts lacking the mHAg-encoding exon. These studies suggest distinct roles for different PANE1 isoforms in resting compared with activated CD19(+) cells, and identify PANE1 as a potential therapeutic target in B-CLL.

Alternative Splicing↗
PubMed2006

Adoptive transfer of allogeneic antigen-specific T cells.

Animal models and human studies of allogeneic hematopoietic cell transplantation (HCT) demonstrate that immunologic nonidentity between donor and recipient is responsible for a graft versus leukemia (GVL) effect that contributes to complete tumor eradication. A variety of immune cells have been implicated in the GVL effect including NK cells, B cells, and CD4(+) and CD8(+) T cells that recognize minor histocompatibility (H) or leukemia-associated antigens. Here we discuss strategies for employing T cells specific for minor H antigens to augment the GVL effect.

Adoptive Transfer↗
PubMed2005

Analysis of transgene-specific immune responses that limit the in vivo persistence of adoptively transferred HSV-TK-modified donor T cells after allogeneic hematopoietic cell transplantation.

The introduction of an inducible suicide gene such as the herpes simplex virus thymidine kinase (HSV-TK) might allow exploitation of the antitumor activity of donor T cells after allogeneic hematopoietic cell transplantation (HCT) without graft versus host disease. However, HSV-TK is foreign, and immune responses to gene-modified T cells could lead to their premature elimination. We show that after the infusion of HSV-TK-modified donor T cells to HCT recipients, CD8+ and CD4+ T-cell responses to HSV-TK are rapidly induced and coincide with the disappearance of transferred cells. Cytokine flow cytometry using an overlapping panel of HSV-TK peptides allowed rapid detection and quantitation of HSV-TK-specific T cells in the blood and identified multiple immunogenic epitopes. Repeated infusion of modified T cells boosted the induced HSV-TK-specific T cells, which persisted as memory cells. These studies demonstrate the need for nonimmunogenic suicide genes and identify a strategy for detection of CD4+ and CD8+ T-cell responses to transgene products that should be generally applicable to monitoring patients on gene therapy trials. The potency of gene-modified T cells to elicit robust and durable immune responses imply this approach might be used for vaccination to elicit T-cell responses to viral or tumor antigens.

Adoptive Transfer↗
PubMed2005

Efficient cross-priming of tumor antigen-specific T cells by dendritic cells sensitized with diverse anti-MICA opsonized tumor cells.

Dendritic cells (DCs) have the capacity to prime tumor-specific T cell responses and are considered as potentially effective vaccines for immunotherapy of cancer. Critical parameters in the development of DC vaccines are the source of tumor antigen (TA) and the mode of DC-loading. Whole tumor cells contain complex assortments of TA, which has been exploited to enhance cross-presentation to CD8 T cells by DCs loaded with anti-syndecan mAb-opsonized myeloma cells. This approach may be broadly improved by targeting the MHC class I chain-related protein A (MICA), which is frequently and abundantly expressed on most if not all types of epithelial cancers but not in normal tissues except intestinal mucosa. Loading of DC with anti-MICA mAb-coated breast, melanoma, or ovarian tumor lines or uncultured ovarian cancer cells efficiently promoted TA cross-presentation and priming of multivalent anti-tumor CD8 and CD4 T cell responses. These were of substantially greater breadth and magnitude than those of T cells primed by peptide-pulsed or apoptotic tumor cell-loaded DCs. These results may advance DC vaccine development and provide a platform for adoptive T cell therapy and TA discovery. These results further suggest that antibody targeting of MICA might be applicable to elicit T cell immunity against tumors of diverse tissue origins in cancer patients.

Antibodies, Monoclonal↗
PubMed2005

Cytomegalovirus disease before hematopoietic cell transplantation as a risk for complications after transplantation.

Cytomegalovirus (CMV) disease in candidates for hematopoietic cell transplantation (HCT) is increasingly observed. Among 22 patients with CMV disease before HCT, the incidence of CMV disease before HCT was significantly higher in patients with severe underlying immune deficiency syndromes compared with patients with hematologic malignancies (P < .001). The lung was the most commonly involved site of infection, followed by the gastrointestinal tract and the retina. Fourteen of 22 patients with CMV disease before HCT responded to treatment and proceeded to HCT; 8 of 22 did not receive an HCT because of fatal CMV disease (n = 2) or other complications (n = 6). Of 14 patients with CMV disease who subsequently underwent HCT, 6 (42%) had CMV disease diagnosed after transplantation despite antiviral prophylaxis or preemptive therapy, and 1 patient had evidence of persistent CMV disease before day 100 after HCT. This proportion was significantly higher than that in patients without CMV disease before HCT during the same time period (day 30, adjusted P = .003; day 100, adjusted P = .02). Thirteen of 14 patients with pretransplantation CMV disease died a median of 36 days after transplantation (range, 19-399 days; adjusted P = .005 compared with CMV-seropositive transplant recipients without a history of pretransplantation CMV disease). In summary, although CMV disease before HCT may be mild and responsive to treatment, it is associated with a high risk of early CMV disease and death after transplantation.

Acyclovir↗
PubMed2005

A UGT2B17-positive donor is a risk factor for higher transplant-related mortality and lower survival after bone marrow transplantation.

We recently identified a human minor histocompatibility (H) antigen, encoded by UDP glycosyltransferase 2 family, polypeptide B17 (UGT2B17), whose immunogenicity results from differential expression in donor and recipient cells as a consequence of a homozygous deletion of the UGT2B17 gene. UGT2B17 is highly expressed in the liver and colon, which are major targets for graft-versus-host disease (GVHD). To assess the significance of homozygous UGT2B17 gene deletion in allogeneic haematopoietic stem cell transplantation (HSCT), we analysed DNA from 435 stem cell transplant recipients with a haematological malignancy and their human leucocyte antigen-identical unrelated bone marrow donors using sequence-specific primer polymerase chain reaction. Homozygous deletion of the UGT2B17 gene was observed in 85% of normal donors and in 82% of patients. The analysis showed no significant association between UGT2B17 mismatch in the GVHD direction and the incidence of acute GVHD, chronic GVHD, relapse, or survival. However, the use of a UGT2B17-positive donor was an independent risk factor for higher transplant-related mortality and lower survival after transplantation. UGT2B17 is a metabolic enzyme for hormones, drugs, and potentially toxic exogenous compounds and is expressed in subsets of haematopoietic cells. Thus, the enzyme function of UGT2B17 in donor cells may affect the outcome of allogeneic HSCT.

Acute Disease↗
PubMed2004

Finding a place for tumor-specific T cells in targeted cancer therapy.

A goal in cancer therapeutics is to develop targeted modalities that distinguish malignant from normal cells. T cells can discriminate diseased cells based on subtle alterations in peptides displayed in association with MHC molecules at the cell surface. Recent success using the adoptive transfer of tumor-specific T cells has fueled optimism that this approach may find a place as a targeted therapy for some human cancers.

Antigen-Presenting Cells↗
PubMed2004

CD27 expression promotes long-term survival of functional effector-memory CD8+ cytotoxic T lymphocytes in HIV-infected patients.

Human immunodeficiency virus (HIV)-specific CD8(+) T cells persist in high frequencies in HIV-infected patients despite impaired CD4(+) T helper response to the virus, but, unlike other differentiated effector cytotoxic T lymphocytes, most continue to express the tumor necrosis factor receptor family member CD27. Because the ligand for CD27 (CD70) is also overexpressed in HIV-infected hosts, we examined the nature of expression and potential functional consequences of CD27 expression on HIV-specific CD8(+) T cells. Analysis of CD27(+) and CD27(-) T cells derived from the same HIV-specific clone revealed that retention of CD27 did not interfere with acquisition of effector functions, and that after T cell receptor stimulation, CD27(+) cells that concurrently were triggered via CD27 exhibited more resistance to apoptosis, interleukin 2 production, and proliferation than CD27(-) T cells. After transfer back into an HIV-infected patient, autologous HIV-specific CD27(-) T cells rapidly disappeared, but CD27(+) T cells derived from the same clone persisted at high frequency. Our findings suggest that the CD27-CD70 interaction in HIV infection may provide CD27(+) CD8(+) T cells with a survival advantage and compensate for limiting or absent CD4(+) T help to maintain the CD8 response.

Adoptive Transfer↗
PubMed2004

Allogeneic hematopoietic cell transplantation for metastatic renal cell carcinoma after nonmyeloablative conditioning: toxicity, clinical response, and immunological response to minor histocompatibility antigens.

PURPOSE: This phase I trial assessed the safety, efficacy, and immunologic responses to minor histocompatibility antigens following nonmyeloablative allogeneic hematopoietic cell transplantation as treatment for metastatic renal cell carcinoma. EXPERIMENTAL DESIGN: Eight patients received conditioning with fludarabine and low-dose total body irradiation followed by hematopoietic cell transplantation from an HLA-matched sibling donor. Cyclosporine and mycophenolate mofetil were administered as posttransplant immunosuppression. Patients were monitored for donor engraftment of myeloid and lymphoid cells, for clinical response by serial imaging, and for immunologic response by in vitro isolation of donor-derived CD8(+) CTLs recognizing recipient minor histocompatibility (H) antigens. RESULTS: All patients achieved initial mixed hematopoietic chimerism with two patients rejecting their graft and recovering host hematopoiesis. Four patients developed acute, grade 2 to 3, graft-versus-host disease and four patients developed extensive chronic graft-versus-host disease. Five patients had progressive disease, two patients had stable disease, and one patient experienced a partial response after receiving donor lymphocyte infusions and IFN-alpha. CD8(+) CTL clones recognizing minor H antigens were isolated from five patients studied. Clones from three patients with a partial response or stable disease recognized antigens expressed on renal cell carcinoma tumor cells. CONCLUSIONS: Treatment of metastatic renal cell carcinoma with allogeneic hematopoietic cell transplantation after nonmyeloablative conditioning with fludarabine/total body irradiation is feasible and may induce tumor regression or stabilization in some patients. CD8(+) CTL-recognizing minor H antigens on tumor cells can be isolated posttransplant and could contribute to the graft-versus-tumor effect. Such antigens may represent therapeutic targets for posttransplant vaccination or adoptive T-cell therapy to augment the antitumor effects of allogeneic hematopoietic cell transplantation.

Adenocarcinoma, Clear Cell↗
PubMed2004

Immune evasion proteins of human cytomegalovirus do not prevent a diverse CD8+ cytotoxic T-cell response in natural infection.

Although cytomegalovirus (CMV) expresses proteins that interfere with antigen presentation by class I major histocompatibility complex (MHC) molecules, CD8+ cytotoxic T cells (CTLs) are indispensable for controlling infection and maintaining latency. Here, a cytokine flow cytometry assay that employs fibroblasts infected with a mutant strain of CMV (RV798), which is deleted of the 4 viral genes that are responsible for interfering with class I MHC presentation, was used to examine the frequency and specificity of the CD8+ CTLs to CMV in immunocompetent CMV-seropositive individuals. A large fraction of the CD8+ CTL response was found to be specific for viral antigens expressed during the immediate early and early phases of virus replication and presented by fibroblasts infected with RV798 but not wild-type CMV. These results demonstrate that the inhibition of class I antigen presentation observed in CMV-infected cells in vitro is not sufficient to prevent the induction of a broad repertoire of CD8+ CTLs after natural infection in vivo. Thus, reconstitution of T-cell immunity in immunodeficient patients by cell therapy or by vaccination may need to target multiple viral antigens to completely restore immunologic control of CMV.

Antigen Presentation↗
PubMed2004

Enhanced transgene expression in quiescent and activated human CD8+ T cells.

The level of expression of retroviral vector-encoded proteins in T cells, decreasing during periods of quiescence, could be an obstacle to their clinical utility. To identify promoter systems that could increase the strength and persistence of transgene expression in primary human CD8(+) T cells, we designed a panel of Moloney retroviral vectors to express a destabilized enhanced green fluorescent protein (d4EGFP) reporter protein (t(1/2) = 4 hr). We found that the promoters phosphoglycerate kinase (Pgk), beta-actin, and long terminal repeat (LTR) produced the highest levels of d4EGFP expression in proliferating T cells, but that expression dramatically declined in quiescent cells with all promoters. To improve gene expression, we examined the effect of the beta-interferon (IFN) scaffold attachment region (SAR). This SAR augmented expression from mammalian promoters in cycling T cells, but had a small effect on maintenance of expression in resting T cells. However, when the SAR was combined with the LTR promoter, it significantly enhanced expression in resting and cycling cells. These data support use of the IFN-beta SAR with the LTR in Moloney retroviral vectors to help sustain gene expression in resting primary human CD8(+) T cells and to enhance gene expression in activated T cells.

CD8-Positive T-Lymphocytes↗
PubMed2003

Pharmacologically regulated Fas-mediated death of adoptively transferred T cells in a nonhuman primate model.

Conditional suicide genes derived from pathogens have been developed to confer drug sensitivity and enhance safety of cell therapy, but this approach is limited by immune responses to the transgene product. We examined a strategy to regulate survival of transferred cells based on induction of apoptosis through oligomerization of a modified human Fas receptor by a bivalent drug (AP1903). Three macaques (Macaca nemestrina) received autologous T cells retrovirally engineered to express a Fas suicide-construct (LV'VFas). High levels of transduced cells were present in blood following cell transfer, but LV'VFas(+) cells declined rapidly after AP1903 administration. A small fraction of LV'VFas(+) cells resisted elimination by AP1903, in part due to insufficient levels of transgene expression in resting T cells, because reactivation of these cells in vitro enhanced sensitivity to AP1903. An immune response to the transgene product was observed, but epitope mapping indicated the response was directed to discrete components of human LV'VFas that were variant with the corresponding macaque sequences. These data demonstrate that chemically induced dimerization can be used to regulate survival of adoptively transferred T cells in vivo.

Adoptive Transfer↗