-
[show abstract]
[hide abstract]
ABSTRACT: The work in our laboratory addresses two interrelated areas of dendritic cell (DC) biology: (1) the role of DCs as mediators
of feedback interactions between NK cells, CD8+ and CD4+ T cells; and (2) the possibility to use such feedback and the paradigms derived from anti-viral responses, to promote the
induction of therapeutic immunity against cancer. We observed that CD8+ T cells and NK cells, the classical “effector” cells, also play “helper” roles, regulating ability of DCs to induce type-1
immune immunity, critical for fighting tumors and intracellular pathogens. Our work aims to delineate which pathways of NK
and CD8+ T cell activation result in their helper activity, and to identify the molecular mechanisms allowing them to induce type-1
polarized DCs (DC1s) with selectively enhanced ability to promote type-1 responses and anti-cancer immunity. The results of
these studies allowed us and our colleagues to design phase I/II clinical trials incorporating the paradigms of DC polarization
and helper activity of effector cells in cancer immunotherapy.
Immunologic Research 04/2012; 36(1):137-146. · 3.03 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Natural killer (NK) cells have been shown to mediate important immunoregulatory "helper" functions in addition to their cytolytic activity. In particular, NK cells are capable of preventing maturation-related dendritic cell (DC) "exhaustion," inducing the development of "type-1 polarized" mature DCs (DC1) with an enhanced ability to produce interleukin (IL)-12p70, a factor essential for type-1 immunity and effective anticancer responses. Here we show that the NK cell-mediated type-1 polarization of DCs can be applied in the context of patients with advanced cancer to enhance the efficacy of DCs in inducing tumor-specific cytotoxic T lymphocytes. NK cells isolated from patients with late-stage (stage III and IV) melanoma responded with high interferon-γ production and the induction of type-1-polarized DCs on exposure to defined combinations of stimulatory agents, including interferon-α and IL-18. The resulting DCs showed strongly-enhanced IL-12p70 production on subsequent T-cell interaction compared with immature DCs (average of 19-fold enhancement) and nonpolarized IL-1β/TNF-α/IL-6/PGE(2)-matured "standard" DCs (average of 215-fold enhancement). Additional inclusion of polyinosinic: polycytidylic acid during NK-DC cocultures optimized the expression of CD80, CD86, CD40, and HLA-DR on the resulting (NK)DC1, increased their CCR7-mediated migratory responsiveness to the lymph node-associated chemokine CCL21, and further enhanced their IL-12-producing capacity. When compared in vitro with immature DCs and nonpolarized standard DCs, (NK)DC1 were superior in inducing functional melanoma-specific cytotoxic T lymphocytes capable of recognizing multiple melanoma-associated antigens and killing melanoma cells. These results indicate that the helper function of NK cells can be used in clinical settings to improve the effectiveness of DC-based cancer vaccines.
Journal of immunotherapy (Hagerstown, Md.: 1997) 03/2011; 34(3):270-8. · 3.20 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Dendritic cells (DC) are increasingly being used as cellular vaccines to treat cancer and infectious diseases. While there have been some promising results in early clinical trials using DC-based vaccines, the inability to visualize non-invasively the location, migration and fate of cells once adoptively transferred into patients is often cited as a limiting factor in the advancement of these therapies. A novel perflouropolyether (PFPE) tracer agent was used to label human DC ex vivo for the purpose of tracking the cells in vivo by (19)F magnetic resonance imaging (MRI). We provide an assessment of this technology and examine its impact on the health and function of the DC.
Monocyte-derived DC were labeled with PFPE and then assessed. Cell viability was determined by examining cell membrane integrity and mitochondrial lipid content. Immunostaining and flow cytometry were used to measure surface antigen expression of DC maturation markers. Functional tests included bioassays for interleukin (IL)-12p70 production, T-cell stimulatory function and chemotaxis. MRI efficacy was demonstrated by inoculation of PFPE-labeled human DC into NOD-SCID mice.
DC were effectively labeled with PFPE without significant impact on cell viability, phenotype or function. The PFPE-labeled DC were clearly detected in vivo by (19)F MRI, with mature DC being shown to migrate selectively towards draining lymph node regions within 18 h.
This study is the first application of PFPE cell labeling and MRI cell tracking using human immunotherapeutic cells. These techniques may have significant potential for tracking therapeutic cells in future clinical trials.
Cytotherapy 04/2010; 12(2):238-50. · 3.63 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: HIV-1 remains sequestered during antiretroviral therapy (ART) and can resume high-level replication upon cessation of ART or development of drug resistance. Reactivity of memory CD8(+) T lymphocytes to HIV-1 could potentially inhibit this residual viral replication, but is largely muted by ART in relation to suppression of viral antigen burden. Dendritic cells (DC) are important for MHC class I processing and presentation of peptide epitopes to memory CD8(+) T cells, and could potentially be targeted to activate memory CD8(+) T cells to a broad array of HIV-1 epitopes during ART.
We show for the first time that HIV-1 peptide-loaded, CD40L-matured DC from HIV-1 infected persons on ART induce IFN gamma production by CD8(+) T cells specific for a much broader range and magnitude of Gag and Nef epitopes than do peptides without DC. The DC also reveal novel, MHC class I restricted, Gag and Nef epitopes that are able to induce polyfunctional T cells producing various combinations of IFN gamma, interleukin 2, tumor necrosis factor alpha, macrophage inhibitory protein 1 beta and the cytotoxic de-granulation molecule CD107a.
There is an underlying, broad antigenic spectrum of anti-HIV-1, memory CD8(+) T cell reactivity in persons on ART that is revealed by DC. This supports the use of DC-based immunotherapy for HIV-1 infection.
PLoS ONE 01/2010; 5(9):e12936. · 4.09 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The ability of cancer vaccines to induce tumor-specific CD8+ T cells in the circulation of cancer patients has been shown to poorly correlate with their clinical effectiveness. In this study, we report that although Ags presented by different types of mature dendritic cells (DCs) are similarly effective in inducing CD8+ T cell expansion, the acquisition of CTL function and peripheral-type chemokine receptors, CCR5 and CXCR3, requires Ag presentation by a select type of DCs. Both "standard" DCs (matured in the presence of PGE2) and type 1-polarized DCs (DC1s) (matured in the presence of IFNs and TLR ligands, which prevent DCs "exhaustion") are similarly effective in inducing CD8+ T cell expansion and acquisition of CD45RO+IL-7R+IL-15R+ phenotype. However, granzyme B expression, acquisition of CTL activity, and peripheral tissue-type chemokine responsiveness are features exclusively exhibited by CD8+ T cells activated by DC1s. This advantage of DC1s was observed in polyclonally activated naive and memory CD8(+) T cells and in blood-isolated melanoma-specific CTL precursors. Our data help to explain the dissociation between the ability of cancer vaccines to induce high numbers of tumor-specific CD8+ T cells in the blood of cancer patients and their ability to promote clinical responses, providing for new strategies of cancer immunotherapy.
The Journal of Immunology 12/2009; 184(2):591-7. · 5.79 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Induction of active tumor-specific immunity in patients with chronic lymphocytic leukemia (CLL) and other hematologic malignancies is compromised by the deficit of endogenous dendritic cells (DCs). In attempt to develop improved vaccination strategies for patients with CLL and other tumors with poorly identified rejection antigens, we tested the ability of ex vivo-generated DCs to cross-present the antigens expressed by CLL cells and to induce CLL-specific, functional CTL responses. Monocyte-derived DCs from CLL patients were induced to mature using a "standard" cytokine cocktail (in IL-1beta, TNF-alpha, IL-6, and PGE2) or using an alpha-type 1-polarized DC (alphaDC1) cocktail (in IL-1beta, TNF-alpha, IFN-alpha, IFN-gamma, and polyinosinic:polycytidylic acid) and were loaded with gamma-irradiated, autologous CLL cells. alphaDC1 from CLL patients expressed substantially higher levels of multiple costimulatory molecules (CD83, CD86, CD80, CD11c, and CD40) than standard DCs (sDCs) and immature DCs, and their expression of CCR7 showed intermediate level. alphaDC1 secreted substantially higher (10-60 times) levels of IL-12p70 than sDCs. Although alphaDC1 and sDCs showed similar uptake of CLL cells, alphaDC1 induced much higher numbers (range, 2.4-38 times) of functional CD8+ T cells against CLL cells. The current demonstration that autologous tumor-loaded alphaDC1 are potent inducers of CLL-specific T cells helps to develop improved immunotherapies of CLL.
Journal of Leukocyte Biology 08/2008; 84(1):319-25. · 4.99 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: CD8(+) T cells have been shown to be capable of either suppressing or promoting immune responses. To reconcile these contrasting regulatory functions, we compared the ability of human effector and memory CD8(+) T cells to regulate survival and functions of dendritic cells (DC). We report that, in sharp contrast to the effector cells (CTLs) that kill DCs in a granzyme B- and perforin-dependent mechanism, memory CD8(+) T cells enhance the ability of DCs to produce IL-12 and to induce functional Th1 and CTL responses in naive CD4(+) and CD8(+) T cell populations. Moreover, memory CD8(+) T cells that release the DC-activating factor TNF-alpha before the release of cytotoxic granules induce DC expression of an endogenous granzyme B inhibitor PI-9 and protect DCs from CTL killing with similar efficacy as CD4(+) Th cells. The currently identified DC-protective function of memory CD8(+) T cells helps to explain the phenomenon of CD8(+) T cell memory, reduced dependence of recall responses on CD4(+) T cell help, and the importance of delayed administration of booster doses of vaccines for the optimal outcome of immunization.
The Journal of Immunology 04/2008; 180(6):3857-65. · 5.79 Impact Factor
-
Yutaro Nakamura,
Payal Watchmaker,
Julie Urban,
Brian Sheridan,
Adam Giermasz,
Fumihiko Nishimura,
Kotaro Sasaki,
Rachel Cumberland,
Ravikumar Muthuswamy, Robbie B Mailliard,
Adriana T Larregina,
Louis D Falo,
William Gooding,
Walter J Storkus,
Hideho Okada,
Robert L Hendricks,
Pawel Kalinski
[show abstract]
[hide abstract]
ABSTRACT: In contrast to the well-established efficacy of preventive vaccines, the effectiveness of therapeutic vaccines remains limited. To develop effective vaccination regimens against cancer, we have analyzed the effect of effector and memory CD8+ T cells on the ability of dendritic cells to mediate the immunologic and antitumor effects of vaccination. We show that in contrast to effector CD8+ T cells that kill antigen-carrying dendritic cells, IFNgamma-producing memory CD8+ T cells act as "helper" cells, supporting the ability of dendritic cells to produce interleukin-12 (IL-12) p70. Promoting the interaction of tumor antigen-carrying dendritic cells with memory-type "heterologous" (tumor-irrelevant) CD8+ T cells strongly enhances the IL-12p70-dependent immunogenic and therapeutic effects of vaccination in the animals bearing established tumors. Our data show that the suppressive and helper functions of CD8+ T cells are differentially expressed at different phases of CD8+ T-cell responses. Selective performance of helper functions by memory (in contrast to effector) CD8+ T cells helps to explain the phenomenon of immune memory and facilitates the design of effective therapeutic vaccines against cancer and chronic infections.
Cancer Research 11/2007; 67(20):10012-8. · 7.86 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: High mobility group box 1 (HMGB1) is one of the recently defined damage-associated molecular pattern molecules, passively released from necrotic cells and secreted by activated macrophage/monocytes. Whether cytolytic cells induce HMGB1 release from tumor cells is not known. We developed a highly sensitive method for detecting intracellular HMGB1 in tumor cells, allowing analysis of the type of cell death and in particular, necrosis. We induced melanoma cell death with cytolytic lymphokine-activated killing (LAK) cells, tumor-specific cytolytic T lymphocytes, TRAIL, or granzyme B delivery and assessed intracellular HMGB1 retention or release to investigate the mechanism of HMGB1 release by cytolytic cells. HMGB1 release from melanoma cells (451Lu, WM9) was detected within 4 h and 24 h following incubation with IL-2-activated PBMC (LAK activity). HLA-A2 and MART1 or gp100-specific cytolytic T lymphocytes induced HMGB1 release from HLA-A2-positive and MART1-positive melanoma cells (FEM X) or T2 cell-loaded, gp100-specific peptides. TRAIL treatment, however, induced HMGB1 release, and it is interesting that this extrinsic pathway-mediated cell death was blocked with the pancaspase inhibitor N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone. Conversely, granzyme B delivery did not induce HMGB1 release. HMGB1, along with other intracellular factors released from tumor cells induced by cytolysis, may be important components of the disordered tumor microenvironment. This has important implications for the immunotherapy of patients with cancer. Specifically, HMGB1 may promote healing or immune reactivity, depending on the nature of the local inflammatory response and the presence (or absence) of immune effectors.
Journal of Leukocyte Biology 02/2007; 81(1):75-83. · 4.99 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Spontaneous or therapy-induced depigmentation in patients with melanoma has long been considered a favourable prognostic indicator. In this report, we isolated T cells infiltrating the depigmented skin of an HLA-A2+/DR4+ patient with melanoma, and detected a very high frequency of CD8+ T cells specific for melanocortin receptor 1 (MC1R), a hormone receptor involved in cutaneous pigmentation. In particular, tissue-infiltrating CD8+ T cells dominantly recognized the novel MC1R52-60 peptide epitope in an HLA-A2-restricted manner, and peptide-reactive CD8+ T cells were also detected in freshly isolated peripheral blood from this patient. Although type 1 CD4+ T-cell responses against MC1R were not detected in fresh tissue isolates, short-term in-vitro stimulation of peripheral blood lymphocytes resulted in the rapid expansion of CD4+ T cells reactive against novel HLA-DR4-presented epitopes derived from the MC1R protein (i.e. MC1R82-95, MC1R105-118 and MC1R149-161). MC1R peptide-specific CD8+ T-cell clones isolated from the depigmented skin of this patient were characterized by comparatively low functional avidity for specific major histocompatibility complex-peptide complexes and were poorly lytic; however, these effector cells were capable of secreting both interferon-gamma and granzyme B against relevant target cells in vitro, and may have played an important role in the induction of leucoderma in situ in this patient.
Melanoma Research 05/2006; 16(2):165-74. · 2.19 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The work in our laboratory addresses two interrelated areas of dendritic cell (DC) biology: (1) the role of DCs as mediators of feedback interactions between NK cells, CD8+ and CD4+ T cells; and (2) the possibility to use such feedback and the paradigms derived from anti-viral responses, to promote the induction of therapeutic immunity against cancer. We observed that CD8+ T cells and NK cells, the classical "effector" cells, also play "helper" roles, regulating ability of DCs to induce type-1 immune immunity, critical for fighting tumors and intracellular pathogens. Our work aims to delineate which pathways of NK and CD8+ T cell activation result in their helper activity, and to identify the molecular mechanisms allowing them to induce type-1 polarized DCs (DC1s) with selectively enhanced ability to promote type-1 responses and anti-cancer immunity. The results of these studies allowed us and our colleagues to design phase I/II clinical trials incorporating the paradigms of DC polarization and helper activity of effector cells in cancer immunotherapy.
Immunologic Research 02/2006; 36(1-3):137-46. · 3.03 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Natural killer (NK) cells and dendritic cells (DCs), two important components of the immune system, can exchange bidirectional activating signals in a positive feedback. Myeloid DCs, the cell type specialised in the presentation of antigen and initiation of antigen-specific immune responses, have recently been documented to be involved in supporting innate immunity, promoting the production of cytokines and cytotoxicity of NK cells, and enhancing their tumouricidal activity. Natural interferon-producing cells/plasmacytoid DCs (IPCs/PDCs) play an additional role in NK cell activation. Reciprocally, NK cells, traditionally considered to be major innate effector cells, have also recently been shown to play immunoregulatory 'helper' functions, being able to activate DCs and to enhance their ability to produce pro-inflammatory cytokines, and to stimulate T helper (Th) 1 and cytotoxic T lymphocyte (CTL) responses of tumour-specific CD4+ and CD8+ T cells. Activated NK cells induce the maturation of myeloid DCs into stable type-1 polarised DCs (DC1), characterised by up to a 100-fold enhanced ability to produce IL-12p70 in response to subsequent interaction with Th cells. In addition, the ability of NK cells to kill tumour cells may facilitate the generation of tumour-related antigenic material, further accelerating the induction of tumour-specific immunity. DC1, induced by NK cells or by NK cell-related soluble factors, are stable, resistant to tumour-related suppressive factors, and demonstrate a strongly enhanced ability to induce Th1 and CTL responses in human in vitro and mouse in vivo models. Compared with the standard mature DCs that are used in clinical trials at present, human NK cell-induced DC1s act as superior inducers of anticancer CTL responses during in vitro sensitisation. This provides a strong rationale for the combined use of NK cells and DCs in the immunotherapy of patients with cancer and patients with chronic infections that are resistant to standard forms of treatment. Stage I/II clinical trials that are being implemented at present should allow evaluation of the immunological and clinical efficacy of combined NK-DC therapy of melanoma and other cancers.
Expert opinion on biological therapy 11/2005; 5(10):1303-15. · 3.22 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: In addition to their cytotoxic activities, natural killer (NK) cells can have immunoregulatory functions. We describe a distinct "helper" differentiation pathway of human CD56+CD3- NK cells into CD56+/CD83+/CCR7+/CD25+ cells that display high migratory responsiveness to lymph node (LN)-associated chemokines, high ability to produce interferon-gamma upon exposure to dendritic cell (DC)- or T helper (Th) cell-related signals, and pronounced abilities to promote interleukin (IL)-12p70 production in DCs and the development of Th1 responses. This helper pathway of NK cell differentiation, which is not associated with any enhancement of cytolytic activity, is induced by IL-18, but not other NK cell-activating factors. It is blocked by prostaglandin (PG)E2, a factor that induces a similar CD83+/CCR7+/CD25+ LN-homing phenotype in maturing DCs. The current data demonstrate independent regulation of the "helper" versus "effector" pathways of NK cell differentiation and novel mechanisms of immunoregulation by IL-18 and PGE2.
Journal of Experimental Medicine 11/2005; 202(7):941-53. · 13.85 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Recent reports demonstrate that natural killer (NK) cells and dendritic cells (DC) support each other's activity in a positive feedback. We observed that activated NK cells induce the maturation of DCs into stable type-1 polarized DCs (DC1), characterized by up to 100-fold enhanced ability to produce IL-12p70 in response to subsequent interaction with Th cells. DC1 induction depends on NK cell-produced IFN-gamma and TNF-alpha, with a possible involvement of additional factors. DC1, induced by NK cells or by NK cell-related soluble factors, are stable, resistant to tumor-related suppressive factors, and show strongly enhanced ability to induce Th1 and CTL responses. In analogy to resting T cells, the induction of "helper" function of NK cells relies on a two-signal activation paradigm. While NKG2D-dependent tumor cell recognition is sufficient to induce the cytotoxic "effector" function of NK cells, the induction of "NK cell help" requires additional signals from type-1 IFNs, products of virally-infected cells, or from IL-2. Compared to non-polarized DCs currently-used in clinical trials, DC1s act as superior inducers of anti-cancer CTL responses during in vitro sensitization. The current data provides rationale for the clinical use of DC1s in cancer and chronic infections (such as HIV), as a new generation DC-based vaccines, uniquely combining fully mature DC status with an elevated, rather than "exhausted" ability to produce bioactive IL-12p70. We are currently implementing stage I/II clinical trials, testing the effectiveness of DC1s induced by NK cells or by NK cell-related factors, as therapeutic vaccines against melanoma.
Molecular Immunology 03/2005; 42(4):535-9. · 2.90 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Using the principle of functional polarization of dendritic cells (DCs), we have developed a novel protocol to generate human DCs combining the three features critical for the induction of type-1 immunity: (a) fully mature status; (b) responsiveness to secondary lymphoid organ chemokines; and (c) high interleukin-12p70 (IL-12p70)-producing ability. We show that IFN-alpha and polyinosinic:polycytidylic acid (p-I:C) synergize with the "classical" type-1-polarizing cytokine cocktail [tumor necrosis factor alpha (TNFalpha)/IL-1beta/IFNgamma], allowing for serum-free generation of fully mature type-1-polarized DCs (DC1). Such "alpha-type-1-polarized DC(s)" (alphaDC1) show high migratory responses to the CCR7 ligand, 6C-kine but produce much higher levels of IL-12p70 as compared to TNFalpha/IL-1beta/IL-6/prostaglandin E2 (PGE2)-matured DCs (sDC), the current "gold standard" in DC-based cancer vaccination. A single round of in vitro sensitization with alphaDC1 (versus sDCs) induces up to 40-fold higher numbers of long-lived CTLs against melanoma-associated antigens: MART-1, gp100, and tyrosinase. Serum-free generation of alphaDC1 allows, for the first time, the clinical application of DCs that combine the key three features important for their efficacy as anticancer vaccines.
Cancer Research 10/2004; 64(17):5934-7. · 7.86 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Neuroblastoma, the most common extracranial solid tumor of childhood, remains a challenge for clinicians and investigators in pediatric surgical oncology. The absence of effective conventional therapies for most patients with neuroblastoma justifies the application of novel, biology-based, experimental approaches to the treatment of this deadly disease. The observation that some aggressive neuroblastomas, particularly in infants, may spontaneously regress suggested that immune-mediated mechanisms may be important in the biology of this disease. Advances in the understanding of the cognate interactions between T cells, antigen-presenting cells and tumors have demonstrated the sentinel role of dendritic cells (DC), the most potent antigen presenting cells, in initiating the cellular immune response to cancer. Until recently the function of DC in pediatric solid tumors, especially neuroblastoma, had not been extensively studied. This review discusses the role of DC in initiating and coordinating the immune response against cancer, the ability of neuroblastoma to induce DC dysregulation at multiple levels by inhibiting DC maturation and function, and the current vaccine strategies being designed to employ the unique ability of DC to promote neuroblastoma regression.
Seminars in Pediatric Surgery 03/2004; 13(1):61-71. · 2.93 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Early stages of viral infections are associated with local recruitment and activation of dendritic cells (DC) and NK cells. Although activated DC and NK cells are known to support each other's functions, it is less clear whether their local interaction in infected tissues can modulate the subsequent ability of migrating DC to induce T cell responses in draining lymph nodes. In this study, we report that NK cells are capable of inducing stable type 1-polarized "effector/memory" DC (DC1) that act as carriers of NK cell-derived helper signals for the development of type 1 immune responses. NK cell-induced DC1 show a strongly elevated ability to produce IL-12p70 after subsequent CD40 ligand stimulation. NK-induced DC1 prime naive CD4+ Th cells for high levels of IFN-gamma, but low IL-4 production, and demonstrate a strongly enhanced ability to induce Ag-specific CD8+ T cell responses. Resting NK cells display stringent activation requirements to perform this novel, DC-mediated, "helper" function. Although their interaction with K562 cells results in effective target cell killing, the induction of DC1 requires a second NK cell-activating signal. Such costimulatory signal can be provided by type I IFNs, common mediators of antiviral responses. Therefore, in addition to their cytolytic function, NK cells also have immunoregulatory activity, induced under more stringent conditions. The currently demonstrated helper activity of NK cells may support the development of Th1- and CTL-dominated type 1 immunity against intracellular pathogens and may have implications for cancer immunotherapy.
The Journal of Immunology 10/2003; 171(5):2366-73. · 5.79 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The authors previously described the complete regression of established neuroblastoma (NB) by the adoptive transfer of syngeneic interleukin-12 transduced dendritic cells (DC) from naive mice. However, some malignancies, like NB, abrogate DC immunostimulation. The authors hypothesize that IL-12 transduction of DC from NB-bearing mice will have the same antitumor properties.
A/J mice (n = 32) with established NB received peritumoral injection of 1 x 10(6) DC (DC, IL-12 DC, day 7 IL-12 DC or day 14 IL-12 DC) on day 7. Tumor growth, phenotype, and ability to induce NK and T cell activity were measured.
Vaccination with naive admIL-12 DC resulted in 100% tumor regression and prolonged survival. Transduced DC induced only partial responses in 75% (day 7) and 25% (day 14) of animals. No differences in phenotype or effector cell activation were noted between admIL-12DC in tumor-bearing or naive mice.
IL-12 DC from tumor-bearing animals have a decreased ability to induce antitumor activity against established murine NB. This decreased capacity appears to be related to the duration of exposure to tumor because day 14 transduced DC had less of an effect than day 7 DC, despite similar phenotypes and ability to activate immune effector cells.
Journal of Pediatric Surgery 07/2003; 38(6):857-62. · 1.45 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Severe systemic toxicities have limited the clinical applications of the potent cytokine, interleukin-2 (IL-2). Recent studies have shown that IL-18 synergizes with IL-2 to enhance cytolytic activity in vitro. Combination therapy allows for IL-2 dose reduction, thus, limiting its toxicity while augmenting natural killer cell activity. The authors hypothesize that IL-18 plus low-dose IL-2 may induce a potent and sustained antitumor response in vivo providing effective immunotherapy for neuroblastoma.
Four groups of A/J mice (n = 28) were inoculated subcutaneously in the right flank with 1 x 10(6) murine neuroblastoma cells (TBJ). On day 7, 5 consecutive daily peritumoral injections were performed with saline (control), human rIL-2 (30,000 IU), murine IL-18 (1 microg), or IL-2 plus IL-18. Tumor growth was monitored, and animals with tumor progression were killed on day 21. Seven weeks after the initial treatment, animals with rejected tumors were rechallenged with 5 x 10(6) cells in the opposite flank. Quantitative data were analyzed by Student's t test.
Rapid tumor growth and death was noted in all control animals by 21 days. Complete tumor eradication was seen in 28% of mice treated with IL-2 (P =.03), 42% of mice treated with IL-18 (P <.05), and 57% of mice treated with of IL-2 plus IL-18 (P <.05). Despite the initial response, all animals failed rechallenge and developed new or recurrent tumors within 7 to 10 days.
Coadministration of low-dose IL-2 plus IL-18 induced a potent primary response to murine neuroblastoma likely caused by activation of natural killer cells in the tumor microenvironment. This combined cytokine therapy strategy was unable to induce sustained immunity to rechallenge. However, dendritic cell vaccination combined with IL-2 plus IL-18 cytokine treatment did allow for the establishment of a complete and durable antitumor response.
Journal of Pediatric Surgery 03/2003; 38(3):301-7; discussion 301-7. · 1.45 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Antigen-driven interaction of dendritic cells (DC) with CD4(+) T(h) cells results in the exchange of bidirectional activating signals. Cross-linking of TCR by MHC class II-bound antigen activates T(h) cells, resulting in their up-regulation of CD40 ligand. Here we show that MHC class II molecules, in addition to their passive role in DC-T(h) cell interaction, can also actively induce DC maturation. Cross-linking of MHC class II molecules on human monocyte-derived DC results in the up-regulation of the surface expression of CD83, CD80, CD86, CD54, CD1a and CD40 molecules, the typical DC maturation-associated markers. It also promotes a rapid homotypic aggregation of DC paralleled by the up-regulation of such adhesion molecules as VLA-4, tissue transglutaminase, CD54 and CD11c. The impact of MHC class II cross-linking upon DC was context dependent. The outcome of MHC class II signaling depends on the maturation status of DC. While the cross-linking of MHC class II on immature DC promoted their maturation, the dominant effect upon the DC that were previously matured was the induction of DC apoptosis. Our current observations indicate that, in addition to the previously reported negative impact of MHC class II-mediated signaling on DC function, it also promotes DC maturation, participating in the enhancement of DC stimulatory function. Importantly, MHC class II-induced DC maturation and apoptosis are mediated by different signaling pathways, sensitive to different sets of inhibitors. This opens the possibility of differential regulation of each of these events in immunotherapy.
International Immunology 10/2002; 14(9):1027-37. · 3.41 Impact Factor
