The potential for monocyte-mediated immunotherapy during infection and malignancy--Part II: in vivo activation by exogenous cytokines and clinical applications

Flexible ZnO-mAb nanoplatforms for selective peripheral blood mononuclear cell immobilization

Cancer is the second cause of death worldwide. This devastating disease requires specific, fast, and affordable solutions to mitigate and reverse this trend. A step towards cancer-fighting lies in the isolation of natural killer (NK) cells, a set of innate immune cells, that can either be used as biomarkers of tumorigenesis or, after autologous transplantation, to fight aggressive metastatic cells. In order to specifically isolate NK cells (which express the surface NKp30 receptor) from peripheral blood mononuclear cells, a ZnO immunoaffinity-based platform was developed by electrodeposition of the metal oxide on a flexible indium tin oxide (ITO)-coated polyethylene terephthalate (PET) substrate. The resulting crystalline and well-aligned ZnO nanorods (NRs) proved their efficiency in immobilizing monoclonal anti-human NKp30 antibodies (mAb), obviating the need for additional procedures for mAb immobilization. The presence of NK cells on the peripheral blood mononuclear cell (PBMCs) fraction was evaluated by the response to their natural ligand (B7-H6) using an acridine orange (AO)-based assay. The successful selection of NK cells from PBMCs by our nanoplatform was assessed by the photoluminescent properties of AO. This easy and straightforward ZnO-mAb nanoplatform paves the way for the design of biosensors for clinic diagnosis, and, due to its inherent biocompatibility, for the initial selection of NK cells for autotransplantation immunotherapies.

Effects of Helminth Eradication on the Immune System

Introduction:

Helminth infection has a profound effect on the immune system. However, the precise nature of the immune changes that are elicited by helminth infection have not been sufficiently characterized. Furthermore, the reversibility of these changes after treatment has not been documented sufficiently. We studied the immune profiles of Ethiopian immigrants to Israel at baseline, that is on arrival and at one-year follow-up and compared individuals who received antihelminth treatment during the study period with those who missed the treatment.

Methods:

A longitudinal follow up study involving different groups of subjects was conducted. Baseline data was recorded from the newly arrived Ethiopian immigrants for a series of peripheral blood tests, including: IgE and Eosinophil levels, T-cell populations, T-cell receptor phenotypes, and cytokine measurement. These tests were all repeated after a 1-year interval. Results were compared between the newly arrived Ethiopian immigrants (NEW-Eth-Il), long term Ethiopian immigrants (LT-Eth-Il), and non Ethiopian Israeli controls (NON-Imm-Il).

Results:

Of the 184 individuals, 111 were NEW-Eth-Il, who had a high prevalence of helminth infection, the immunological changes were elevated IgE levels and eosinophil counts, decreased CD4/CD8 ratio, increased proportion of HLA-DR+CD3+, HLA-DR+CD4+ and HLA-DR+CD8+ cells, decreased proportion of CD45RA+CD4+ (naive) and CD28+CD8+ cells, increased proportion of CD45RO+CD4+ (memory) cells, and increased secretion of IL-4 and IL-5 (Th2 type cytokines). In the 42 LT-Eth-Il participants, who all had negative tests for helminth infection, we did not observe these immune changes and their immune profile did not differ markedly from that of the NON-Imm-Il controls. The follow-up immune profiles of 33 NEW-Eth-Il who received succesful antihelminth treatment, showed a significant normalization in the above-mentioned variables that was not observed in the 19 NEW-Eth-Il who missed and did not receive the antihelminth treatment.

Conclusions:

These findings demonstrate that helminth infection is associated with profound immune changes that are normalized within a short time after helminth eradication. They also strengthen the hypothesis that effective antihelminth interventions, in areas endemic for intestinal helminths, may have an impact on AIDS and tuberculosis epidemics.

Head and neck squamous cell carcinoma spheroid- and monocyte spheroid-stimulated IL-6 and monocyte chemotactic protein-1 secretion are related to TNM stage, inflammatory state and tumor macrophage density

Monocyte fragment (F)-spheroid-stimulated and F-spheroid IL-6 and monocyte chemotactic protein (MCP)-1 secretion are related to inflammatory state, macrophage density and the TNM stage of patients with head and neck squamous cell carcinoma (HNSCC). Fragment (F)-spheroids from HNSCC patients in vitro secrete and stimulate autologous monocytes to secrete IL-6 and MCP-1. The aim of this investigation was to study this cytokine secretion in relation to other cytokines, spheroid composition and host factors.In series I (n=14) the densities of epithelial cells, fibroblasts and macrophages were determined in sections from F-spheroids and donor tissue. In series II (n=17) the TNM stage, donor inflammatory state, macrophage density and the secretion of F-spheroid- and monocyte F-spheroid-stimulated IL-6, MCP-1 and tumor necrosis factor (TNF)-alpha were determined. Epithelial cells were partly replaced by interstitial tissue during spheroid formation. Malignant (M) F-spheroids secreted more MCP-1 than benign (B) F-spheroids. No F-spheroid secreted measurable amounts of TNF-alpha. Monocytes secreted more IL-6 when co-cultured with MF- compared to BF-spheroids. Monocyte IL-6 MF- and MCP-1 MB-spheroid-stimulated secretion correlated with macrophage density. In addition, there was an association between MF- and BF-spheroid-stimulated monocyte cytokine secretion, as well as between BF- and MF-spheroid-stimulated MCP-1 secretion. An inverse relation was also noted between the erythrocyte sedimentation rate at monocyte harvest and the monocyte MCP-1 F-spheroid responses.

Inhibition of spontaneous development of liver tumors by inoculation with dendritic cells loaded with hepatocellular carcinoma cells in C3H/HeNCRJ mice

We attempted to prevent spontaneous development of liver tumors by s.c. inoculation with DCs loaded with syngeneic HCC cells in C3H/HeNCrj mice. A new cell line, MIH-2, was established from an HCC that had developed spontaneously in a C3H/HeNCrj mouse. Bone marrow-derived DCs were loaded with irradiated MIH-2 cells by treatment with PEG. Fluorescence microscopy and flow-cytometric analysis showed that about 45% of PEG-treated DCs and MIH-2 cells (DC/MIH-2) were DCs loaded with MIH-2 cells. Thirteen-month-old mice received inoculations of DC/MIH-2 (9 x 10(5)/mouse) 4 times at 6-day intervals and were killed at 16 months of age to assess liver tumors. The incidence of liver tumors in these mice was significantly lower than that in mice not receiving inoculations (p < 0.05) but similar to that in 13-month-old mice (the age at which inoculation started), indicating that inoculation inhibited the development of new tumors. Splenocytes from inoculated mice, but not those from uninoculated mice, showed cytotoxic activity against MIH-2 cells. Cytotoxic activity was not elicited by CD4(+) T cells, CD8(+) T cells, or DX5(+) cells isolated from splenocytes but was elicited by adherent cells, identified as CD11b(+) macrophages. CD4(+) T cells, but not CD8(+) T cells, from inoculated mice produced IFN-gamma by incubation with DC/MIH-2. Cytotoxicity by splenocytes was attenuated by anti-IFN-gamma antibody. Immunization with DCs loaded with syngeneic HCC cells induces CD4(+) T cells that produce IFN-gamma by response to antigen of HCC, which would lead to macrophage activation to kill liver tumor cells at an early stage.

Autologous stem-cell transplantation restores the functional properties of CD14+CD16+ monocytes in patients with myeloma and lymphoma

The CD14+CD16+ monocytes appear to be important to immune defense against infection, as these cells are very potent with respect to tumor necrosis factor (TNF) production, phagocytosis, and antigen presentation. Myeloablative high-dose chemotherapy (HDT) and subsequent autologous stem-cell transplantation (ASCT) are being used increasingly for therapy of hematological malignancies, but the pronounced immunosuppression renders the patients prone to infection. To determine the functional properties of CD14+CD16+ monocytes under these conditions, 15 patients with lymphoma or myeloma were examined. Before HDT, the ratio of CD14+CD16+ cells to the population of the classical CD14++ monocytes was 0.28 +/- 0.12; this ratio changed during the course of HDT and ASCT in favor of the CD14+CD16+ monocytes to a maximum of 12.4 +/- 7.8 (P<0.001) on day 3.5 +/- 1.6 after transplanation (Tx) and returned to 0.11 +/- 0.07 (P<0.001) after engraftment on day 11.3 +/- 2.2. Although the absolute number of classical CD14++ monocytes declined to less than 1/microl at the nadir, the number of CD14+CD16+monocytes fell from 29.7 +/- 9.8/microl to 4.5 +/- 3.0/microl at the nadir and increased to 13.8 +/- 9.8/microl at the day of discharge from the hospital. Flow cytometric analysis of phagocytosis of fluorescein isothiocyanate (FITC)-labeled Escherichia coli showed that 30 +/- 10% CD14+CD16+ monocytes of patients were FITC-positive before Tx, and at engrafment, the percentage of FITC-positive cells had doubled to 60 +/- 6% (healthy controls, 41+/-7%). When determining generation of reactive oxygen species after E. coli ingestion, the CD14+CD16+ monocytes showed a decreased response before Tx (32+/-12% positve cells), which increased to 53 +/- 24% after ASCT. The median fluorescence intensity of human leukocyte antigen (HLA)-DR expression on the CD14+CD16+ monocytes increased from 11 +/- 6 before Tx to 17 +/- 11 after Tx, and the production of TNF after lipopolysaccharide showed no remarkable difference (46+/-13 vs. 49+/-14 channels). At the same time, expression of TNF and of HLA-DR showed a dramatic decrease in the CD14++ monocytes. Taken together after stem-cell Tx, the function of the CD14++ monocytes is impaired, and the functional properties of CD14+CD16+ monocytes recover, indicating that these cells may be important for defense against infections post-ASCT.

Enzyme-linked immunospot assays provide a sensitive tool for detection of cytokine secretion by monocytes

Blood monocytes as well as tissue-differentiated macrophages play a pivotal role in controlling immune reactions. Monocytes regulate the extent, nature, and duration of immune responses by secretion of cytokines. Interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-alpha), IL-10, and IL-12 are of particular interest, since IL-12 shifts the immune response towards a Th1 type, facilitating the production of, e.g., TNF-alpha and IL-6, while IL-10 counteracts Th1 responses and promotes the production of Th2-related cytokines such as IL-4. A tight regulation of these four cytokines keeps the balance and decides whether Th1 or Th2 will predominate in immune reactions. Enzyme-linked immunospot (ELISPOT) assays are among the most-sensitive and -specific methods available for cytokine research. They permit ex vivo identification of individual cells actively secreting cytokines. In the present study we prepared monocytes from healthy subjects' blood and adapted ELISPOT assays to define optimal conditions to detect and enumerate monocytes secreting IL-6, TNF-alpha, IL-10, and IL-12. The optimal time for monocyte incubation was 24 h, and optimal monocyte numbers (in cells per well) were 2,000 for IL-6, 1,000 for TNF-alpha, 50,000 for IL-10, and 100,000 for enumeration of IL-12 secreting monocytes. Among healthy subjects, 10% +/- 5% of the monocytes secreted IL-6, 12% +/- 12% secreted TNF-alpha, 0.1% +/- 0.1% secreted IL-10, and 0.2% +/- 0.3% secreted IL-12 (values are means +/- standard deviations). In conclusion, ELISPOT assays constitute a valuable tool to enumerate monocytes secreting IL-6, TNF-alpha, IL-10, and IL-12 and probably to enumerate monocytes secreting other cytokines and proteins.

Monocyte-macrophage system as targets for immunomodulation by intravenous immunoglobulin

Pooled human intravenous immunoglobulin (IVIg) has been used successfully to treat or ameliorate the clinical manifestations of humoral immune deficiencies, haematological disorders, HIV infection and many other diseases states. However, the mechanism of action of IVIg remains unclear. Several mechanisms of action of IVIg have been proposed. These include Fcy receptor blockade, accelerated clearance of endogenous pathogenic auto-antibodies, inhibition of components of the complement cascade, neutralization of super-antigens and bacterial toxins as well as anti-cytokine and anti-idiotype effects. A major contributor to host immunity and immune surveillance against infection, tissue or cell damage and malignancy is the monocyte/macrophage system. Monocyte-directed inflammation is a desirable consequence of microbiological or malignant challenge. However, monocyte hyperactivity may contribute to certain pathological conditions. These include the systemic inflammatory response syndrome (SIRS), septic shock, other dysregulated inflammatory disorders and auto-immunity. Novel therapies that can suppress the hyperactive state or correct monocyte/macrophage dysfunction without compromising normal host cell-mediated immunity are desirable. In this review, we discuss the immunomodulatory effects of IVIg focussing particularly upon the monocyte/macrophage system in pertinent disease states.