Antitumor Monoclonal Antibodies Enhance Cross-Presentation of Cellular Antigens and the Generation of Myeloma-specific Killer T Cells by Dendritic Cells

The mechanism of antitumor effect of monoclonal antibodies (mAbs) is not fully understood. Here we show that coating myeloma cells with anti–syndecan-1 antibody promotes cross-presentation of cellular antigens by dendritic cells (DCs) to autologous T cells from healthy donors. The tumor cells treated with anti–syndecan-1 or isotype-matched control antibody were fed to HLA-mismatched monocyte-derived immature DCs. Tumor cell–loaded mature DCs induced a strong CD8+ T cell response that was specific for the cancer-testis (C-T) antigens expressed in the tumor. The CD8+ T cells killed peptide-pulsed targets, as well as myeloma tumor cells. Importantly, mAbs-coated tumor-loaded DCs were consistently superior to DCs loaded with peptides or dying cells for eliciting tumor-specific killer T cells. This enhanced cross-presentation was not due to enhanced tumor cell uptake or to DC maturation. When mixtures of NY-Eso-1-positive and -negative myeloma cells were captured by DCs, the anti–syndecan-1 antibody had to be on the NY-Eso-1-positive cells to elicit NY-Eso-1–specific response. Cross-presentation was inhibited by pretreatment of DCs with Fcγ receptor blocking antibodies. Targeting of mAb-coated tumors to DCs may contribute to the efficacy of tumor-reactive mAb and offers a new strategy for immunotherapy

Antigen-specific inhibition of effector T cell function in humans after injection of immature dendritic cells

Immunostimulatory properties of dendritic cells (DCs) are linked to their maturation state. Injection of mature DCs rapidly enhances antigen-specific CD4+ and CD8+ T cell immunity in humans. Here we describe the immune response to a single injection of immature DCs pulsed with influenza matrix peptide (MP) and keyhole limpet hemocyanin (KLH) in two healthy subjects. In contrast to prior findings using mature DCs, rejection of immature DCs in both subjects led to the specific inhibition of MP-specific CD8+ T cell effector function in freshly isolated T cells and the appearance of MP-specific interleukin 10-producing cells. When pre-and postimmunization T cells were boosted in culture, there were greater numbers of MP-specific major histocompatibility complex tetramer-binding cells after immunization, but these had reduced interferon γ production and lacked killer activity. These data demonstrate the feasibility of antigen-specific inhibition of effector T cell function in vivo in humans and urge caution with the use of immature DCs when trying to enhance tumor microbial immunity

Rapid generation of broad T-cell immunity in humans after a single injection of mature dendritic cells

Dendritic cells (DCs) are potent antigen-presenting cells that initiate protective T-cell immunity in mice. To study the immunogenicity of DCs in humans, we injected 9 healthy subjects subcutaneously with a control injection of autologous monocyte-derived, mature DCs, followed 4-6 weeks later by DCs pulsed with keyhole limpet hemocyanin (KLH), HLA-A*0201- positive restricted influenza matrix peptide (MP), and tetanus toxoid (TT). Four more subjects received these antigens without DCs. Injection of unpulsed DCs, or antigens alone, failed to immunize. Priming of CD4+ T cells to KLH was observed in all 9 subjects injected with KLH-pulsed DCs, and boosting of TT-specific T-cell immunity was seen in 5 of 6 subjects injected with TT- pulsed DCs. Injection of antigen-pulsed DCs led to a severalfold increase in freshly isolated MP-specific, IFN-γ-secreting CD8+ T cells in all 6 HLA- A*0201-positive subjects, as early as 7 days after injection. When T cells were boosted in culture, there was an increase in MHC tetramer-binding cells and cytotoxic T cells after DC vaccination. These data provide the first controlled evidence of the immunogenicity of DCs in humans, and demonstrate that a single injection of mature DCs rapidly expands T-cell immunity

Role of Tissue-Resident Memory in Intra-Tumor Heterogeneity and Response to Immune Checkpoint Blockade

Tissue-resident memory T (TRM) cells are a distinct subset of memory T cells that reside in non-lymphoid tissues for prolonged periods of time without significant recirculation providing continued immune surveillance at these sites. Recent studies suggest that TRM cells are also enriched within tumor tissue. Expression of inhibitory immune checkpoints (ICPs) is particularly enriched on this subset of tumor-infiltrating T cells, suggesting that they are major targets for newer therapies targeting ICPs such as the programmed death-1 pathway. Recent studies suggest that tissue restriction of these cells without recirculation may also lead to heterogeneity of TRM cells within individual metastatic lesions, ultimately leading to inter-lesional diversity. Thus, individual metastatic lesions may contain genomically distinct immune microenvironments that impact both evolution of tumors as well as the mechanisms underlying response and resistance to immune therapies. Understanding the biology of TRM cells infiltrating tumors will be essential to improving immune-based approaches in diverse settings

A Reversible Defect in Natural Killer T Cell Function Characterizes the Progression of Premalignant to Malignant Multiple Myeloma

We studied the function of antitumor T and natural killer T (NKT) cells from the blood and tumor bed in 23 patients with premalignant gammopathy, nonprogressive myeloma, or progressive multiple myeloma. We show that antitumor killer T cells can be detected in patients with both progressive or nonprogressive myeloma. Vα24+Vβ11+ invariant NKT cells are detectable in the blood and tumor bed of all cohorts. However, freshly isolated NKT cells from both the blood and tumor bed of patients with progressive disease, but not nonprogressive myeloma or premalignant gammopathy, have a marked deficiency of ligand-dependent interferon-γ production. This functional defect can be overcome in vitro using dendritic cells pulsed with the NKT ligand, α-galactosylceramide (α-GalCer). Fresh myeloma cells express CD1d, and can be efficiently killed by autologous NKT cells. We hypothesize that presentation of tumor derived glycolipids by myeloma cells leads to NKT dysfunction in vivo. These data demonstrate that clinical progression in patients with monoclonal gammopathies is associated with an acquired but potentially reversible defect in NKT cell function and support the possibility that these innate lymphocytes play a role in controlling the malignant growth of this incurable B cell tumor in patients

Selective blockade of the inhibitory Fcγ receptor (FcγRIIB) in human dendritic cells and monocytes induces a type I interferon response program

The ability of dendritic cells (DCs) to activate immunity is linked to their maturation status. In prior studies, we have shown that selective antibody-mediated blockade of inhibitory FcγRIIB receptor on human DCs in the presence of activating immunoglobulin (Ig) ligands leads to DC maturation and enhanced immunity to antibody-coated tumor cells. We show that Fcγ receptor (FcγR)–mediated activation of human monocytes and monocyte-derived DCs is associated with a distinct gene expression pattern, including several inflammation-associated chemokines, as well as type 1 interferon (IFN) response genes, including the activation of signal transducer and activator of transcription 1 (STAT1). FcγR-mediated STAT1 activation is rapid and requires activating FcγRs. However, this IFN response is observed without a detectable increase in the expression of type I IFNs themselves or the need to add exogenous IFNs. Induction of IFN response genes plays an important role in FcγR-mediated effects on DCs, as suppression of STAT1 by RNA interference inhibited FcγR-mediated DC maturation. These data suggest that the balance of activating/inhibitory FcγRs may regulate IFN signaling in myeloid cells. Manipulation of FcγR balance on DCs and monocytes may provide a novel approach to regulating IFN-mediated pathways in autoimmunity and human cancer

Capability of 19-litre polycarbonate plastic water cooler containers for efficient solar water disinfection (SODIS): field case studies in India, Bahrain and Spain.

The small treated volume (typically ~2 litres) associated with polyethylene terephthalate (PET) bottles that are most frequently used in solar water disinfection (SODIS), is a major obstacle to uptake of this water treatment technology in the developing world. In order to address this problem we have conducted a series of experiments in Spain, Bahrain and India, to assess the efficacy of large volume (19 litres) transparent plastic (polycarbonate) water cooler/dispenser containers (WDCs) as SODIS reactors to inactivate Escherichia coli and Enterococcus faecalis, under strong natural sunlight. Reduction values of 6 log10 units (LRV = 6.0) have been observed using WDCs in each location. Additional comparisons between 2-L PET bottles and 19-L indicate that WDCs provide bacterial inactivation similar in both systems. SODIS disinfection experiments in turbid water (100 NTU) in both reactors showed very good inactivation efficiency. LRVs of 7.2 and 7.8 were obtained for E. coli in WDC and 2-L PET bottles, respectively, and in the case of E. faecalis LRV = 5.7 and 7.9 were observed. These studies demonstrate that under conditions of strong sunlight and mild temperature, 19 litre water dispenser containers can be used to provide adequate volumes of SODIS treated water for households or larger community applications such as schools or clinics in the developing world

Sustained expansion of NKT cells and antigen-specific T cells after injection of α-galactosyl-ceramide loaded mature dendritic cells in cancer patients

Natural killer T (NKT) cells are distinct glycolipid reactive innate lymphocytes that are implicated in the resistance to pathogens and tumors. Earlier attempts to mobilize NKT cells, specifically, in vivo in humans met with limited success. Here, we evaluated intravenous injection of monocyte-derived mature DCs that were loaded with a synthetic NKT cell ligand, α-galactosyl-ceramide (α-GalCer; KRN-7000) in five patients who had advanced cancer. Injection of α-GalCer–pulsed, but not unpulsed, dendritic cells (DCs) led to >100-fold expansion of several subsets of NKT cells in all patients; these could be detected for up to 6 mo after vaccination. NKT activation was associated with an increase in serum levels of interleukin-12 p40 and IFN-γ inducible protein-10. In addition, there was an increase in memory CD8(+) T cells specific for cytomegalovirus in vivo in response to α-GalCer–loaded DCs, but not unpulsed DCs. These data demonstrate the feasibility of sustained expansion of NKT cells in vivo in humans, including patients who have advanced cancer, and suggest that NKT activation might help to boost adaptive T cell immunity in vivo

Estrogen as therapy for breast cancer

High-dose estrogen was generally considered the endocrine therapy of choice for postmenopausal women with breast cancer prior to the introduction of tamoxifen. Subsequently, the use of estrogen was largely abandoned. Recent clinical trial data have shown clinically meaningful efficacy for high-dose estrogen even in patients with extensive prior endocrine therapy. Preclinical research has demonstrated that the estrogen dose-response curve for breast cancer cells can be shifted by modification of the estrogen environment. Clinical and laboratory data together provide the basis for developing testable hypotheses of management strategies, with the potential of increasing the value of endocrine therapy in women with breast cancer