Humilidad F. Gallardo

Overexpression of TAR sequences renders cells resistant to human immunodeficiency virus replication

Overexpression of TAR-containing sequences (TAR decoys) was used to render cells resistant to HIV replication. A chimeric tRNA(meti)-TAR transcription unit contained in a double copy murine retroviral vector was used to express high levels of HIV-1 TAR-containing transcripts in CEM SS cells. Replication of HIV-1 was inhibited over 99% in cells expressing chimeric tRNA-TAR transcripts, but an amphotropic murine retrovirus replicated normally in these cells. Expression of TAR sequences in CEM SS cells had no adverse effects on cell viability, indicating that essential cellular factors are not being sequestered in these cells. TAR decoy RNA-mediated HIV inhibition may also be effective against natural HIV isolates in spite of their hypervariable nature, as suggested by the fact that replication of SIVmac was also inhibited in cells expressing HIV-1 TAR decoys.

CTLA-4 blockade enhances polyfunctional NY-ESO-1 specific T cell responses in metastatic melanoma patients with clinical benefit

Blockade of inhibitory signals mediated by cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) has been shown to enhance T cell responses and induce durable clinical responses in patients with metastatic melanoma. The functional impact of anti-CTLA-4 therapy on human immune responses is still unclear. To explore this, we analyzed immune-related adverse events and immune responses in metastatic melanoma patients treated with ipilimumab, a fully human anti-CTLA-4 monoclonal antibody. Fifteen patients were selected on the basis of availability of suitable specimens for immunologic monitoring, and eight of these showed evidence of clinical benefit. Five of the eight patients with evidence of clinical benefit had NY-ESO-1 antibody, whereas none of seven clinical non-responders was seropositive for NY-ESO-1. All five NY-ESO-1 seropositive patients had clearly detectable CD4+ and CD8+ T cells against NY-ESO-1 following treatment with ipilimumab. One NY-ESO-1 seronegative clinical responder also had a NY-ESO-1 CD4+ and CD8+ T cell response, possibly related to prior vaccination with NY-ESO-1. Among five clinical non-responders analyzed, only one had a NY-ESO-1 CD4+ T cell response and this patient did not have detectable anti-NY-ESO-1 antibody. Overall, NY-ESO-1-specific T cell responses increased in frequency and functionality during anti-CTLA-4 treatment, revealing a polyfunctional response pattern of IFN-γ, MIP-1β and TNF-α. We therefore suggest that CTLA-4 blockade enhanced NY-ESO-1 antigen-specific B cell and T cell immune responses in patients with durable objective clinical responses and stable disease. These data provide an immunologic rationale for the efficacy of anti-CTLA-4 therapy and call for immunotherapeutic designs that combine NY-ESO-1 vaccination with CTLA-4 blockade.

Integrated NY-ESO-1 antibody and CD8+ T-cell responses correlate with clinical benefit in advanced melanoma patients treated with ipilimumab

Ipilimumab, a monoclonal antibody against cytotoxic T lymphocyte antigen 4 (CTLA-4), has been shown to improve survival in patients with advanced metastatic melanoma. It also enhances immunity to NY-ESO-1, a cancer/testis antigen expressed in a subset of patients with melanoma. To characterize the association between immune response and clinical outcome, we first analyzed NY-ESO-1 serum antibody by ELISA in 144 ipilimumab-treated patients with melanoma and found 22 of 140 (16%) seropositive at baseline and 31 of 144 (22%) seropositive following treatment. These NY-ESO-1–seropositive patients had a greater likelihood of experiencing clinical benefit 24 wk after ipilimumab treatment than NY-ESO-1–seronegative patients (P = 0.02, relative risk = 1.8, two-tailed Fisher test). To understand why some patients with NY-ESO-1 antibody failed to experience clinical benefit, we analyzed NY-ESO-1–specific CD4+ and CD8+ T-cell responses by intracellular multicytokine staining in 20 NY-ESO-1–seropositive patients and found a surprising dissociation between NY-ESO-1 antibody and CD8 responses in some patients. NY-ESO-1–seropositive patients with associated CD8+ T cells experienced more frequent clinical benefit (10 of 13; 77%) than those with undetectable CD8+ T-cell response (one of seven; 14%; P = 0.02; relative risk = 5.4, two-tailed Fisher test), as well as a significant survival advantage (P = 0.01; hazard ratio = 0.2, time-dependent Cox model). Together, our data suggest that integrated NY-ESO-1 immune responses may have predictive value for ipilimumab treatment and argue for prospective studies in patients with established NY-ESO-1 immunity. The current findings provide a strong rationale for the clinical use of modulators of immunosuppression with concurrent approaches to favor tumor antigen-specific immune responses, such as vaccines or adoptive transfer, in patients with cancer.

Classification of Clear-Cell Sarcoma as a Subtype of Melanoma by Genomic Profiling

PURPOSE To develop a genome-based classification scheme for clear-cell sarcoma (CCS), also known as melanoma of soft parts (MSP), which would have implications for diagnosis and treatment. This tumor displays characteristic features of soft tissue sarcoma (STS), including deep soft tissue primary location and a characteristic translocation, t(12;22)(q13;q12), involving EWS and ATF1 genes. CCS/MSP also has typical melanoma features, including immunoreactivity for S100 and HMB45, pigmentation, MITF-M expression, and a propensity for regional lymph node metastases. MATERIALS AND METHODS RNA samples from 21 cell lines and 60 pathologically confirmed cases of STS, melanoma, and CCS/MSP were examined using the U95A GeneChip (Affymetrix, Santa Clara, CA). Hierarchical cluster analysis, principal component analysis, and support vector machine (SVM) analysis exploited genomic correlations within the data to classify CCS/MSP. RESULTS Unsupervised analyses demonstrated a clear distinction between STS and melanoma and, furthermore, showed that CCS/MSP cluster with the melanomas as a distinct group. A supervised SVM learning approach further validated this finding and provided a user-independent approach to diagnosis. Genes of interest that discriminate CCS/MSP included those encoding melanocyte differentiation antigens, MITF, SOX10, ERBB3, and FGFR1. CONCLUSION Gene expression profiles support the classification of CCS/MSP as a distinct genomic subtype of melanoma. Analysis of these gene profiles using the SVM may be an important diagnostic tool. Genomic analysis identified potential targets for the development of therapeutic strategies in the treatment of this disease.

Cerebrospinal fluid β2-microglobulin in patients with AIDS dementia complex : an expanded series including response to zidovudine treatment

ConclusionsCSF (β2M may be a valuable marker of ADC severity and response to antiviral therapy.

Recombinant human interleukin-7 (CYT107) promotes T-cell recovery after allogeneic stem cell transplantation

Delays in immune recovery after allogeneic hematopoietic stem cell transplantation (allo-HSCT) are associated with increased risks of infection and relapse. IL-7 has a central role in T-cell development and survival and enhances immune recovery in murine models of allo-HSCT. We performed a phase 1 trial of r-hIL-7 (CYT107) in recipients of T-cell depleted allo-HSCTs. Twelve patients were treated with escalating doses of r-hIL-7 administered weekly for 3 weeks. The study drug was well tolerated with only one patient developing acute skin GVHD. At baseline, patients were profoundly lymphopenic. CYT107 induced a doubling in CD4(+) and CD8(+) T cells. The main effect of IL-7 was an expansion of effector memory T cells, the predominant subset identified in our patients. There was no significant effect on CD4(+)CD25(+)FoxP3(+) T cells, NK, or B cells. Importantly, we not only saw quantitative increases in T cells after a short course of IL-7 but also demonstrated an increase in functional T cells, including viral-specific T cells that recognize CMV. Enhanced TCR diversity was also observed after treatment. Our results indicate that r-hIL-7 can enhance immune recovery after a T cell-depleted allo-HSCT without causing significant GVHD or other serious toxicity (www.clinicaltrials.gov; NCT00684008).

Phase I/II study of GM-CSF DNA as an adjuvant for a multipeptide cancer vaccine in patients with advanced melanoma.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) enhances immune responses by inducing dendritic cell proliferation, maturation, and migration and B and T lymphocyte expansion and differentiation. The potency of DNA vaccines can be enhanced by the addition of DNA encoding cytokines, acting as molecular adjuvants. We conducted a phase I/II trial of human GM-CSF DNA in conjunction with a multipeptide vaccine (gp100 and tyrosinase) in stage III/IV melanoma patients. Nineteen human leukocyte antigen (HLA)-A*0201(+) patients were treated. Three dose levels were studied: 100, 400, and 800 mcg DNA/injection, administered subcutaneously (SQ) every month with 500 mcg of each peptide. In the dose-ranging study, 3 patients were treated at each dose level. The remaining patients were then treated at the highest dose. Most toxicities were grade 1 injection site reactions. Eight patients (42%) developed CD8+ T-cell responses, defined by a ≥3 SD increase in baseline reactivity to tyrosinase or gp100 peptide in tetramer or intracellular cytokine staining assays. There was no relationship between dose and T-cell response. Responding T cells had an effector memory cell phenotype. Polyfunctional T cells were also demonstrated. At a median of 31 months follow-up, median survival has not been reached. Human GM-CSF DNA was found to be a safe adjuvant.

CTLA-4 blockade increases antigen-specific CD8+ T cells in prevaccinated patients with melanoma: Three cases

BackgroundAnti-cytotoxic T-lymphocyte antigen-4 (CTLA-4) antibodies, such as ipilimumab, have generated measurable immune responses to Melan-A, NY-ESO-1, and gp100 antigens in metastatic melanoma. Vaccination against such targets has potential for immunogenicity and may produce an effector-memory T-cell response.MethodsTo determine the effect of CTLA-4 blockade on antigen-specific responses following vaccination, in-depth immune monitoring was performed on three ipilimumab-treated patients prevaccinated with gp100 DNA (IMF-24), gp100209–217 and tyrosinase peptides plus GM-CSF DNA (IMF-32), or NY-ESO-1 protein plus imiquimod (IMF-11); peripheral blood mononuclear cells were analyzed by tetramer and/or intracellular cytokine staining following 10-day culture with HLA-A*0201-restricted gp100209–217 (ITDQVPFSV), tyrosinase369–377 (YMDGTMSQV), or 20-mer NY-ESO-1 overlapping peptides, respectively. Tumors from IMF-32 were analyzed by immunohistochemistry to help elucidate mechanism(s) underlying tumor escape.ResultsFollowing vaccination, patients generated weak to no CD4+ or CD8+ T-cell response specific to the vaccine antigen but demonstrated increases in effector-memory (CCR7loCD45RAlo) tetramer+CD8+ T cells. After ipilimumab induction, patients experienced a robust, although sometimes transient, antigen-specific response for gp100 (IMF-32 and IMF-24) or NY-ESO-1 (IMF-11) and produced polyfunctional intracellular cytokines. Primary and metastatic tumors expressed tyrosinase but not gp100 or class I/II MHC molecules.ConclusionVaccination induced a measurable antigen-specific T-cell response that increased following CTLA-4 blockade, potentially “boosting” the vaccine-primed response. Tumor escape may be related to antigen loss or lack of MHC expression necessary for immune activity. These results in a limited number of patients support the need for further research into combining vaccination with ipilimumab and provide insight into mechanisms underlying tumor escape.

Immunologic Response to Xenogeneic gp100 DNA in Melanoma Patients: Comparison of Particle-Mediated Epidermal Delivery with Intramuscular Injection

Purpose: Prior studies show that i.m. injection of xenogeneic orthologues of melanosomal antigens (tyrosinase, gp100) induces CD8+ T-cell responses to the syngeneic protein. To further define the optimal vaccination strategy, we conducted a pilot clinical trial comparing i.m. injection with particle-mediated epidermal delivery (PMED). Experimental Design: Human leukocyte antigen (HLA)-A*0201+ disease–free melanoma patients were randomized to the PMED or i.m. arm, receiving eight vaccinations over 4 months. Patients received 4 μg or 2,000 μg per injection, respectively, of mouse gp100 DNA. Peripheral blood mononuclear cells were collected, cultured with gp100 peptides, and analyzed by tetramer and intracellular cytokine staining for responses to HLA-A*0201–restricted gp100 epitopes [gp100209-217 (ITDQVPFSV) and gp100280-288 (YLEPGPVTA)]. Results: Twenty-seven patients with stage IIB-IV melanoma were analyzable for immune response. The only common toxicity was grade 1 injection site reaction in nine patients with no intergroup difference, and one dose-limiting toxicity of acute hypersensitivity occurred in a PMED patient with undiagnosed gold allergy. Four of 27 patients produced gp100 tetramer+CD8+ T cells, all carrying the CCR7loCD45RAlo effector-memory phenotype. Five of 27 patients generated IFN-γ+CD8+ T cells, one who was also tetramer-positive. Overall, vaccination induced a response in 30% of patients, which was not significantly associated with study arm or clinical outcome. However, the PMED group showed a trend toward increased IFN-γ+CD8+ T-cell generation (P = 0.07). Conclusion: A comparable efficacy and safety profile was shown between the i.m. and PMED arms, despite a significantly decreased dose of DNA used for PMED injection. Clin Cancer Res; 16(15); 4057–65. ©2010 AACR.

Optimization and validation of a robust human T-cell culture method for monitoring phenotypic and polyfunctional antigen-specific CD4 and CD8 T-cell responses

BACKGROUND AIMS Monitoring cellular immune responses is one prerequisite for the rational development of cancer vaccines. METHODS We describe an extensive effort to optimize and validate quantitatively an in vitro T-cell culture method by determining the phenotype and function of both CD4(+) and CD8(+) T cells, including measurement of the phenotype markers CCR7, CD45RA, CD28 and CD27 and the functional markers interferon (IFN)-gamma, interleukin (IL)-2, macrophage inflammatory protein (MIP)-1beta, tumor necrosis factor (TNF)-alpha and CD107a. RESULTS Autologous peripheral blood mononuclear cells (PBMC) were potent stimulators that expanded antigen (Ag)-specific CD8(+) T cells during short-term culture with the addition of IL-2 and IL-15 cytokines. Polyfunctional Ag-specific CD4(+) and CD8(+) T cells were detectable using this method. CONCLUSIONS Our culture system represents a robust human T-cell culture protocol that permits phenotypic, quantitative and qualitative evaluation of vaccine-induced CD4(+) and CD8(+) T-cell responses.