-
The Journal of Infectious Diseases Dec 2017Regulatory T cells (Tregs) suppress T-cell immune activation and human immunodeficiency virus type 1 (HIV-1) replication, but the role of Tregs in HIV-1 reservoir...
BACKGROUND
Regulatory T cells (Tregs) suppress T-cell immune activation and human immunodeficiency virus type 1 (HIV-1) replication, but the role of Tregs in HIV-1 reservoir persistence is poorly defined.
METHODS
Tregs were depleted by denileukin diftitox in humanized mice with chronic HIV-1 infection. Viral replication in lineage cells was determined by p24 expression. Levels of HIV-1 RNA and DNA in human cells, as well as replication-competent-virus-producing cells, were measured to quantified viral replication and reservoirs.
RESULTS
Treg depletion resulted in a blip of HIV-1 replication in T cells but not in myeloid cells. The major activated reservoir cells were memory CD4+ T cells in vivo. Interestingly, the transient activation of viral replication led to HIV-1 reservoir reduction after viremia resuppression, as indicated by the quantity of HIV-1 DNA and replication-competent-virus-producing cells. Furthermore, we demonstrated that Tregs use cyclic adenosine monophosphate (cAMP)-dependent protein kinase A pathway to inhibit HIV-1 activation and replication in resting conventional T cells in vitro.
CONCLUSION
Tregs suppress HIV-1 replication in T cells and contribute to HIV-1 reservoir persistence. cAMP produced in Tregs is involved in their suppression of viral gene activation and expression. Treg depletion combined with combination antiretroviral therapy provides a novel strategy for HIV-1 cure.
Topics: Animals; Cyclic AMP; DNA, Viral; Disease Models, Animal; HIV Core Protein p24; HIV Infections; HIV-1; Humans; Leukocyte Reduction Procedures; Mice; Mice, SCID; RNA, Viral; T-Lymphocytes, Helper-Inducer; T-Lymphocytes, Regulatory; Viral Load; Virus Replication
PubMed: 29045701
DOI: 10.1093/infdis/jix547 -
Journal of Virology Sep 2020Regulatory T cells (Tregs) may be key contributors to the HIV/SIV latent reservoir, since they harbor high levels of HIV/SIV; reverse CD4 T cell immune activation...
Regulatory T cells (Tregs) may be key contributors to the HIV/SIV latent reservoir, since they harbor high levels of HIV/SIV; reverse CD4 T cell immune activation status, increasing the pool of resting CD4 T cells; and impair CD8 T cell function, favoring HIV persistence. We tested the hypothesis that Treg depletion is a valid intervention toward an HIV cure by depleted Tregs in 14 rhesus macaque (RM) controllers infected with SIVsab, the virus that naturally infects sabaeus monkeys, through different strategies: administration of an anti-CCR4 immunotoxin, two doses of an anti-CD25 immunotoxin (interleukin-2 with diphtheria toxin [IL-2-DT]), or two combinations of both. All of these treatments resulted in significant depletion of the circulating Tregs (>70%) and their partial depletion in the gut (25%) and lymph nodes (>50%). The fractions of CD4 T cells expressing -67 increased up to 80% in experiments containing IL-2-DT and only 30% in anti-CCR4-treated RMs, paralleled by increases in the inflammatory cytokines. In the absence of ART, plasma virus rebounded to 10 vRNA copies/ml by day 10 after IL-2-DT administration. A large but transient boost of the SIV-specific CD8 T cell responses occurred in IL-2-DT-treated RMs. Such increases were minimal in the RMs receiving anti-CCR4-based regimens. Five RMs received IL-2-DT on ART, but treatment was discontinued because of high toxicity and lymphopenia. As such, while all treatments depleted a significant proportion of Tregs, the side effects in the presence of ART prevent their clinical use and call for different Treg depletion approaches. Thus, based on our data, Treg targeting as a strategy for HIV cure cannot be discarded. Regulatory T cells (Tregs) can decisively contribute to the establishment and persistence of the HIV reservoir, since they harbor high levels of HIV/SIV, increase the pool of resting CD4 T cells by reversing their immune activation status, and impair CD8 T cell function, favoring HIV persistence. We tested multiple Treg depletion strategies and showed that all of them are at least partially successful in depleting Tregs. As such, Treg depletion appears to be a valid intervention toward an HIV cure, reducing the size of the reservoir, reactivating the virus, and boosting cell-mediated immune responses. Yet, when Treg depletion was attempted in ART-suppressed animals, the treatment had to be discontinued due to high toxicity and lymphopenia. Therefore, while Treg targeting as a strategy for HIV cure cannot be discarded, the methodology for Treg depletion has to be revisited.
Topics: Animals; Anti-Retroviral Agents; CD4-Positive T-Lymphocytes; CD8-Positive T-Lymphocytes; Cytokines; Diphtheria Toxin; Immunity, Cellular; Inflammation; Interleukin-2; Interleukin-2 Receptor alpha Subunit; Lymphopenia; Macaca mulatta; Primates; Receptors, CCR4; Recombinant Fusion Proteins; Simian Immunodeficiency Virus; T-Lymphocytes, Regulatory; Virus Latency
PubMed: 32669326
DOI: 10.1128/JVI.00533-20 -
Cancer Science Mar 2018E7777, a recombinant cytotoxic fusion protein comprising diphtheria toxin fragments A and B and human interleukin-2, shares an amino acid sequence with denileukin...
E7777, a recombinant cytotoxic fusion protein comprising diphtheria toxin fragments A and B and human interleukin-2, shares an amino acid sequence with denileukin diftitox but has improved purity and an increased percentage of active protein monomer species. A phase I study was carried out to evaluate the tolerability, safety, pharmacokinetics, and antitumor activity of E7777 in Japanese patients with relapsed/refractory peripheral and cutaneous T-cell lymphoma. E7777 (6, 12, and expanded 9 μg/kg/day) was given to 13 patients by i.v. infusion on five consecutive days per 21-day cycle. Dose-limiting toxicities, including increased alanine aminotransferase, hyponatremia (n = 2), hypokalemia, lymphopenia, fatigue, hypoalbuminemia, rash, and increased lipase (n = 1), were observed in all three patients in the 12 μg/kg/day cohort, whereas two of six patients in the 9 μg/kg/day cohort showed decreased appetite or fatigue. The maximum tolerated and recommended dose of E7777 was 9 μg/kg/day for five consecutive days per 21-day cycle. The objective response rate was 38% (5/13) and did not appear to depend on tumor expression of CD25. E7777 was well tolerated, assuming careful management of adverse events during treatment, and preliminary but clinically meaningful antitumor activity was observed. Subsequent studies of E7777 for T-cell lymphomas are warranted. This study was registered with www.ClinicalTrials.gov (NCT1401530).
Topics: Administration, Oral; Adult; Aged; Antineoplastic Agents; Cohort Studies; Diphtheria Toxin; Drug Administration Schedule; Drug Resistance, Neoplasm; Female; Humans; Infusions, Intravenous; Interleukin-2; Lymphoma, T-Cell, Cutaneous; Male; Maximum Tolerated Dose; Middle Aged; Neoplasm Recurrence, Local; Recombinant Fusion Proteins; Skin Neoplasms; Treatment Outcome; Young Adult
PubMed: 29363235
DOI: 10.1111/cas.13513 -
Journal of Immunotherapy (Hagerstown,... 2019Cellular immunotherapy using allogeneic natural killer (NK) cells may overcome chemotherapy-refractory acute myeloid leukemia. Our goal was to document NK cell... (Clinical Trial)
Clinical Trial
Cellular immunotherapy using allogeneic natural killer (NK) cells may overcome chemotherapy-refractory acute myeloid leukemia. Our goal was to document NK cell homing/persistence in the bone marrow following adoptive immunotherapy. Our cohort included 109 patients who received NK cell therapy for refractory acute myeloid leukemia following lymphodepleting conditioning +/- denileukin diftitox, +/- low-dose total body irradiation. We evaluated the NK cell density in bone marrow core biopsies performed an average of 14 days after NK cell transfer using a CD56 immunohistochemical stain. The NK cell density in core biopsies showed only moderate correlation with NK cell percentage in bone marrow aspirates evaluated by flow cytometry (rs=0.48) suggesting that distribution of CD56 cells in the bone marrow niche offers unique insight into NK cell homing. Better leukemia control was associated with increased NK cell density, such that patients with <5% blasts had a higher NK cell density (P=0.01). As well, NK cell density above the median of reference group was significantly associated with morphologic remission of leukemia (P=0.01). Moreover, the NK cell density varied significantly between conditioning protocols. Our findings suggest that the use of low-dose irradiation or CD25-targeting immunocytokine (denileukin diftitox, IL2DT) as part of conditioning results in increased NK cell homing/persistence in the bone marrow. These novel results will help guide future immunotherapy with NK cells.
Topics: Adolescent; Adult; Aged; Bone Marrow; Child; Child, Preschool; Female; Humans; Immunotherapy, Adoptive; Killer Cells, Natural; Leukemia, Myeloid, Acute; Male; Middle Aged; Young Adult
PubMed: 30489431
DOI: 10.1097/CJI.0000000000000250 -
Immunopharmacology and Immunotoxicology Dec 2017We have reported previously that DAB389IL-2 recombinant fusion toxin targets IL-2R bearing CD4 cells, and suppresses demyelinating disease in acute (A) - and chronic (C)...
CONTEXT
We have reported previously that DAB389IL-2 recombinant fusion toxin targets IL-2R bearing CD4 cells, and suppresses demyelinating disease in acute (A) - and chronic (C) - experimental autoimmune encephalomyelitis (EAE) animal models of multiple sclerosis.
OBJECTIVES
The present study was undertaken to investigate the effect of DAB389IL-2 treatment on various cytokine-secreting cell populations in A-EAE and C-EAE mice.
MATERIALS AND METHODS
The effects of DAB389IL-2 at doses of 200-, 800-, or 1600 kU administered i.v. on days 11-13 and 15 on the clinical score and cytokine-secreting cell populations were examined using flow cytometry.
RESULTS
C-EAE mice treated with 1600kU DAB389IL-2, but not A-EAE mice treated with 800 kU had significantly reduced disease. The CD3+CD25+ sub-population in spleens and spinal cords of A-EAE mice treated with 800 kU DAB389IL-2 a was increased, whereas in C-EAE mice treated with 1600 kU this population was increased. DABIL-2 treatment reduced CD3CD4, CD3CD8, CD4CD8, CD3IL-2, CD3IFN-γ and CD3TNF-α T cell subpopulations in the spinal cord in A-EAE, and C-EAE mice on day 16. CD11b+ macrophages that were IL-2-, IFN-γ-, and TNF-α- positive were reduced in A-EAE mice. DAB389IL-2 treatment reduced CD19 B-cells positive for IL-2 or CD11b in the spinal cord in acute and chronic disease. DAB389IL-2 treatment also reduced lymph node CD3CD8, CD4CD8, CD3CD25 populations on day 16, and lymph node CD3IL-10 and peripheral blood CD3CD25 populations on day 24.
DISCUSSION AND CONCLUSIONS
Our study demonstrates that DABIL-2 fusion toxin suppresses EAE in a dose-dependent manner, and alters inflammatory cell sub-populations during disease development.
Topics: Animals; B-Lymphocytes; CD4-Positive T-Lymphocytes; Diphtheria Toxin; Encephalomyelitis, Autoimmune, Experimental; Female; Interferon-gamma; Interleukin-10; Interleukin-2; Lymph Nodes; Lymphocyte Activation; Macrophages; Mice; Multiple Sclerosis; Recombinant Fusion Proteins; Spinal Cord; Spleen; Tumor Necrosis Factor-alpha
PubMed: 28929835
DOI: 10.1080/08923973.2017.1369099 -
Cancer Immunology, Immunotherapy : CII Mar 2018We report a novel phase 2 clinical trial in patients with poor prognosis refractory non-Hodgkin lymphoma (NHL) testing the efficacy of haploidentical donor natural... (Randomized Controlled Trial)
Randomized Controlled Trial
We report a novel phase 2 clinical trial in patients with poor prognosis refractory non-Hodgkin lymphoma (NHL) testing the efficacy of haploidentical donor natural killer (NK) cell therapy (NK dose 0.5-3.27 × 10 NK cells/kg) with rituximab and IL-2 (clinicaltrials.gov NCT01181258). Therapy was tolerated without graft-versus-host disease, cytokine release syndrome, or neurotoxicity. Of 14 evaluable patients, 4 had objective responses (29%; 95% CI 12-55%) at 2 months: 2 had complete response lasting 3 and 9 months. Circulating donor NK cells persisted for at least 7 days after infusion at the level 0.6-16 donor NK cells/µl or 0.35-90% of total CD56 cells. Responding patients had lower levels of circulating host-derived Tregs (17 ± 4 vs. 307 ± 152 cells/µL; p = 0.008) and myeloid-derived suppressor cells at baseline (6.6 ± 1.4% vs. 13.0 ± 2.7%; p = 0.06) than non-responding patients. Lower circulating Tregs correlated with low serum levels of IL-10 (R = 0.64; p < 0.003; n = 11), suggestive of less immunosuppressive milieu. Low expression of PD-1 on recipient T cells before therapy was associated with response. Endogenous IL-15 levels were higher in responders than non-responding patients at the day of NK cell infusion (mean ± SEM: 30 ± 4; n = 4 vs. 19.0 ± 4.0 pg/ml; n = 8; p = 0.02) and correlated with day 14 NK cytotoxicity as measured by expression of CD107a (R = 0.74; p = 0.0009; n = 12). In summary, our observations support development of donor NK cellular therapies for advanced NHL as a strategy to overcome chemoresistance. Therapeutic efficacy may be further improved through disruption of the immunosuppressive environment and infusion of exogenous IL-15.
Topics: Adolescent; Adult; Aged; Biomarkers, Tumor; Child; Donor Selection; Female; Follow-Up Studies; Graft vs Host Disease; Hematopoietic Stem Cell Transplantation; Humans; Immunosuppressive Agents; Immunotherapy, Adoptive; Killer Cells, Natural; Lymphoma, Non-Hodgkin; Male; Middle Aged; Myeloid-Derived Suppressor Cells; Prognosis; Programmed Cell Death 1 Receptor; Prospective Studies; Receptors, Immunologic; Remission Induction; Transplantation, Homologous; Young Adult
PubMed: 29218366
DOI: 10.1007/s00262-017-2100-1