Inability to mediate prolonged reduction of regulatory T Cells after transfer of autologous CD25-depleted PBMC and interleukin-2 after lymphodepleting chemotherapy.
Journal of immunotherapy (Hagerstown, Md. : 1997)
Powell, D. J., de Vries, C. R., Allen, T., Ahmadzadeh, M., Rosenberg, S. A.
; 30 (4): 438?47
Abstract
CD25CD4 regulatory T cells (Treg) regulate peripheral self-tolerance and possess the ability to suppress antitumor responses, which may explain the poor clinical response of cancer patients undergoing active immunization protocols, and provides the rationale for neutralizing Treg cells in vivo to strengthen local antitumor immune responses. Because interleukin-2 (IL-2) mediates tumor regression in about 15% of treated patients but simultaneously increases Treg cells, we hypothesized that transient elimination of Treg cells will enhance the clinical effectiveness of IL-2 therapy. In the current study, 5 patients with metastatic melanoma who were refractory to prior IL-2 received a lymphodepleting preparative regimen followed by the adoptive transfer of autologous lymphocytes depleted of CD25 Treg cells and high-dose IL-2 administration. CD25 cells were eliminated from patient leukapheresis samples using a clinical-grade, large-scale immunomagnetic system, leaving CD8 and CD25CD4 T cells intact. In the early aftermath of CD25 Treg cell-depleted cell infusion, CD25FOXP3+ CD4 Treg cells rapidly repopulated the peripheral blood of treated patients with 18% to 63% of CD4 T cells expressing FOXP3. Recovering CD25CD4 T cells exhibited suppressive activity against CD25CD4 effector T-cell proliferation in vitro. No patient experienced objective tumor regression or autoimmunity. Our results indicate that in vivo transfer of autologous CD25-depleted mononuclear populations to lymphopenic patients in combination with high-dose IL-2 is not sufficient to mediate prolonged reduction of Treg cells after IL-2 administration.
View details for DOI 10.1097/CJI.0b013e3180600ff9
View details for PubMedID 17457218
View details for PubMedCentralID PMC2140222
Abstract
Bacteriophage are abundant at sites of bacterial infection, but their effects on mammalian hosts are unclear. We have identified pathogenic roles for filamentous Pf bacteriophage produced by Pseudomonas aeruginosa (Pa) in suppression of immunity against bacterial infection. Pf promote Pa wound infection in mice and are associated with chronic human Pa wound infections. Murine and human leukocytes endocytose Pf, and internalization of this single-stranded DNA virus results in phage RNA production. This triggers Toll-like receptor 3 (TLR3)- and TIR domain-containing adapter-inducing interferon-? (TRIF)-dependent type I interferon production, inhibition of tumor necrosis factor (TNF), and the suppression of phagocytosis. Conversely, immunization of mice against Pf prevents Pa wound infection. Thus, Pf triggers maladaptive innate viral pattern-recognition responses, which impair bacterial clearance. Vaccination against phage virions represents a potential strategy to prevent bacterial infection.
View details for PubMedID 30923196
Abstract
Effective immunotherapeutic strategies require the ability to generate a systemic antigen-specific response capable of impacting both primary and metastatic disease. We have built on our oncolytic vaccinia a granulocyte-macrophage colony-stimulating factor (GM-CSF) strategy by adding recombinant tumor antigen to increase the response in the tumor microenvironment and systemically. In the present study, orthotopic growth of a syngeneic HER2/neu-overexpressing mammary carcinoma in FVB/N mice (NBT1) was associated with increased Gr1(+)CD11b(+) myeloid-derived suppressor cells (MDSCs) both systemically and in the tumor microenvironment. This MDSC population had inhibitory effects on the HER2/neu-specific Th1 immune response. VVneu and VVGMCSF are recombinant oncolytic vaccinia viruses that encode HER2/neu and GM-CSF, respectively. Naive FVB mice vaccinated with combined VVneu and VVGMCSF given systemically developed systemic HER2/neu-specific immunity. NBT1-bearing mice became anergic to systemic immunization with combined VVneu and VVGMCSF. Intratumoral VVGMCSF failed to result in systemic antitumor immunity until combined with intratumoral VVneu. Infection/transfection of the tumor microenvironment with combined VVGMCSF and VVneu resulted in development of systemic tumor-specific immunity, reduction in splenic and tumor MDSC and therapeutic efficacy against tumors. These studies demonstrate the enhanced efficacy of oncolytic vaccinia virus recombinants encoding combined tumor antigen and GM-CSF in modulating the microenvironment of MDSC-rich tumors.
View details for DOI 10.1038/cgt.2015.2
View details for PubMedID 25633483
View details for PubMedCentralID PMC4397129
Abstract
Through the adoptive transfer of lymphocytes after host immunodepletion, it is possible to mediate objective cancer regression in human patients with metastatic melanoma. However, the generation of tumor-specific T cells in this mode of immunotherapy is often limiting. Here we report the ability to specifically confer tumor recognition by autologous lymphocytes from peripheral blood by using a retrovirus that encodes a T cell receptor. Adoptive transfer of these transduced cells in 15 patients resulted in durable engraftment at levels exceeding 10% of peripheral blood lymphocytes for at least 2 months after the infusion. We observed high sustained levels of circulating, engineered cells at 1 year after infusion in two patients who both demonstrated objective regression of metastatic melanoma lesions. This study suggests the therapeutic potential of genetically engineered cells for the biologic therapy of cancer.
View details for DOI 10.1126/science.1129003
View details for Web of Science ID 000241031200051
View details for PubMedID 16946036
View details for PubMedCentralID PMC2267026
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