Immune rejection of a large sarcoma following cyclophosphamide and IL-12 treatment requires both NK and NK T cells and is associated with the induction of a novel NK T cell population

CCR5 drives NK cell-associated airway damage in pulmonary ischemia-reperfusion injury

Primary graft dysfunction (PGD) limits clinical benefit after lung transplantation, a life-prolonging therapy for patients with end-stage disease. PGD is the clinical syndrome resulting from pulmonary ischemia-reperfusion injury (IRI), driven by innate immune inflammation. We recently demonstrated a key role for NK cells in the airways of mouse models and human tissue samples of IRI. Here, we used 2 mouse models paired with human lung transplant samples to investigate the mechanisms whereby NK cells migrate to the airways to mediate lung injury. We demonstrate that chemokine receptor ligand transcripts and proteins are increased in mouse and human disease. CCR5 ligand transcripts were correlated with NK cell gene signatures independently of NK cell CCR5 ligand secretion. NK cells expressing CCR5 were increased in the lung and airways during IRI and had increased markers of tissue residency and maturation. Allosteric CCR5 drug blockade reduced the migration of NK cells to the site of injury. CCR5 blockade also blunted quantitative measures of experimental IRI. Additionally, in human lung transplant bronchoalveolar lavage samples, we found that CCR5 ligand was associated with increased patient morbidity and that the CCR5 receptor was increased in expression on human NK cells following PGD. These data support a potential mechanism for NK cell migration during lung injury and identify a plausible preventative treatment for PGD.

Natural killer cells activated through NKG2D mediate lung ischemia-reperfusion injury

Pulmonary ischemia-reperfusion injury (IRI) is a clinical syndrome of acute lung injury that occurs after lung transplantation or remote organ ischemia. IRI causes early mortality and has no effective therapies. While NK cells are innate lymphocytes capable of recognizing injured cells, their roles in acute lung injury are incompletely understood. Here, we demonstrated that NK cells were increased in frequency and cytotoxicity in 2 different IRI mouse models. We showed that NK cells trafficked to the lung tissue from peripheral reservoirs and were more mature within lung tissue. Acute lung ischemia-reperfusion injury was blunted in a NK cell-deficient mouse strain but restored with adoptive transfer of NK cells. Mechanistically, NK cell NKG2D receptor ligands were induced on lung endothelial and epithelial cells following IRI, and antibody-mediated NK cell depletion or NKG2D stress receptor blockade abrogated acute lung injury. In human lung tissue, NK cells were increased at sites of ischemia-reperfusion injury and activated NK cells were increased in prospectively collected human bronchoalveolar lavage in subjects with severe IRI. These data support a causal role for recipient peripheral NK cells in pulmonary IRI via NK cell NKG2D receptor ligation. Therapies targeting NK cells may hold promise in acute lung injury.

Prospects for NK Cell Therapy of Sarcoma

Simple Summary

Sarcomas are a group of aggressive tumors originating from mesenchymal tissues. Patients with advanced disease have poor prognosis due to the ineffectiveness of current treatment protocols. A subset of lymphocytes called natural killer (NK) cells is capable of effective surveillance and clearance of sarcomas, constituting a promising tool for immunotherapeutic treatment. However, sarcomas can cause impairment in NK cell function, associated with enhanced tumor growth and dissemination. In this review, we discuss the molecular mechanisms of sarcoma-mediated suppression of NK cells and their implications for the design of novel NK cell-based immunotherapies against sarcoma.

Abstract

Natural killer (NK) cells are innate lymphoid cells with potent antitumor activity. One of the most NK cell cytotoxicity-sensitive tumor types is sarcoma, an aggressive mesenchyme-derived neoplasm. While a combination of radical surgery and radio- and chemotherapy can successfully control local disease, patients with advanced sarcomas remain refractory to current treatment regimens, calling for novel therapeutic strategies. There is accumulating evidence for NK cell-mediated immunosurveillance of sarcoma cells during all stages of the disease, highlighting the potential of using NK cells as a therapeutic tool. However, sarcomas display multiple immunoevasion mechanisms that can suppress NK cell function leading to an uncontrolled tumor outgrowth. Here, we review the current evidence for NK cells’ role in immune surveillance of sarcoma during disease initiation, promotion, progression, and metastasis, as well as the molecular mechanisms behind sarcoma-mediated NK cell suppression. Further, we apply this basic understanding of NK–sarcoma crosstalk in order to identify and summarize the most promising candidates for NK cell-based sarcoma immunotherapy.

Role of Interleukin-12 in Protection against Pulmonary Infection with Methicillin-Resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) is a common pathogen associated with nosocomial pneumonia and is an increasing threat for severe community-acquired pneumonia. We have now investigated the role of interleukin-12 (IL-12) in protective immunity against lung infection with MRSA. The importance of IL-12 in protection from pulmonary MRSA infection was demonstrated by the finding that IL-12p35-deficient mice had a lower survival rate, higher bacterial burdens in lung and spleen, and decreased expression of interferon gamma (IFN-γ) in the lung compared to wild-type mice. These effects were completely reversed by replacement intranasal therapy with recombinant IL-12. Furthermore, exogenous IL-12 treatment of wild-type mice 24 h before pulmonary challenge with a lethal dose of MRSA significantly improved bacterial clearance and resulted in protection from death. The IL-12-treated mice had increased numbers of lung natural killer (NK) cells and neutrophils and higher levels of IFN-γ in the lung and serum compared to untreated mice. The major source of IL-12-driven IFN-γ expression in the lung was the NK cell, and the direct target of pulmonary IFN-γ was the lung macrophage, as shown using mice with a macrophage-specific defect in interferon gamma (IFN-γ) signaling (MIIG mice). Importantly, combination therapy with linezolid and IL-12 following intranasal MRSA infection significantly increased survival compared to that of mice receiving linezolid or IL-12 alone. These results indicate that IL-12-based immunotherapy may hold promise for treatment of MRSA pneumonia.

ZPDC glycoprotein (24 kDa) induces apoptosis and enhances activity of NK cells in N-nitrosodiethylamine-injected Balb/c

Natural killer (NK) cells have anti-tumor activity in hepatocellular carcinoma (HCC) using secreting granules and cytotoxic ability. Recently, we isolated glycoprotein from Zanthoxylum piperitum DC (ZPDC) has anti-oxidant effect and anti-cancer effect. The objective of this study was to determine whether ZPDC glycoprotein enhances activity of NK cells and induces apoptosis of liver cancer cells in diethylnitrosamine (DEN)-treated Balb/c mice. This study evaluated the secreting of perforin and granzyme B and cytotoxicity of NK cells, interleukin (IL)-2 and IL-12, apoptosis-related factors (bid, cytochrome c, and caspase-3) in liver tissue using Immunoblot and ELISA. The results demonstrated that ZPDC glycoprotein (20mg/kg, BW) induces secretion of perforin and granzyme B and NK cells activity. Also, it induces expression of apoptosis-related factors (bid, cytochrome c, and caspase-3) in liver tissues. Collectively, ZPDC glycoprotein may have potential applications to prevent hepatocarcinogenesis without immunosuppression.

Effects of the antlered form of Ganoderma lucidum on tumor growth and metastasis in cyclophosphamide-treated mice

We examined the alleviation of cyclophosphamide-induced immunodepression by the antlered form of Ganoderma lucidum (G. lucidum AF) and also evaluated the anti-tumor and anti-metastatic effects of G. lucidum AF in cyclophosphamide-treated mice. G. lucidum AF alleviated cyclophosphamide-induced decrease in body weight, natural killer (NK) activity, interferon (IFN)-gamma production, and cytotoxic T lymphocyte (CTL) activity, and inhibited the abnormal increase and decrease in interleukine (IL)-4 level due to cyclophosphamide administration. Post-treatment with cyclophosphamide and G. lucidum AF significantly inhibited tumor growth in MM 46-bearing mice. When Lewis lung carcinoma cells were injected into mice after a cyclophosphamide administration, metastasis of these cells to the lung was increased, but G. lucidum AF suppressed it. The anti-tumor and anti-metastatic effects of the combination of G. lucidum AF and cyclophosphamide might influence the modulatory effects of G. lucidum AF on both cellular and humoral immunity. These findings suggest that G. lucidum AF would be beneficial in alleviating the reduction of immune response by chemotherapeutic anti-cancer drugs.

Treatment of SCCVII tumors with systemic chemotherapy and Interleukin-12 gene therapy combination

Cyclophosphamide and Interleukin-12 (IL-12) have been successfully used in clinical trials for treating malignancies. In this study, we explore the coadministration of cyclophosphamide and IL-12 plasmid DNA followed by electroporation for treating SCCVII in mice. Cyclophosphamide, IL-12 plasmid DNA, or a combination of both was injected intramuscularly in mice bearing SCCVII tumors. The tumor growth, survival, cytokine expression, cytotoxic T lymphocyte activity, and vascular density were analyzed. Coadministration of cyclophosphamide and IL-12 plasmid DNA via electroporation delays tumor growth and increases survival in mice. This combination therapy has great potential to be translated to a clinical setting for treating malignancies.

Significant differences of lymphocytes isolated from ascites of patients with ovarian cancer compared to blood and tumor lymphocytes. Association of CD3+CD56+ cells with platinum resistance

OBJECTIVES

Tumor infiltrating lymphocytes (TILs) and T regulatory cells (Tregs) have been associated with prognosis in ovarian cancer, but their prognostic significance in ascites has not been studied. We performed a prospective study of T lymphocytes isolated from ascites from patients with ovarian carcinoma and we compared them with the respective populations in blood and tumors.

METHODS

Mononuclear cells from ascites (n=71) and blood were isolated by Ficoll, while tumor lymphocytes (n=20) were obtained upon mechanical dissociation. Phenotypic analysis was performed with flow cytometry. Ascites from 10 patients with cirrhosis was used as control.

RESULTS

Tregs containing CD4(+)CD25(+) cells, NK-T containing CD3(+)CD56(+) cells and CD69 and HLADR expression of CD4 and CD8 lymphocytes were significantly increased in tumor ascites compared to blood and control ascites. A selective accumulation of these populations in the ascites of cancer patients, was suggested by the significantly higher ascites/blood (A/B) ratios in cancer patients but not controls. Cancer cell content in ascites was correlated with CD4(+)CD25(+), CD4(+)CD69(+), CD4(+)HLADR(+) and CD8(+)CD69(+) cells. There was no correlation of lymphocyte populations between ascites and samples from peritoneal metastases. Higher tumor grade was associated with increased A/B CD4(+)CD25(+) ratio and reduced CD3(+)CD56(+) cells, while platinum resistance was associated with reduced A/B CD3(+)CD56(+) ratio.

CONCLUSIONS

There are significant differences of CD3(+)CD56(+) and CD25(+)CD4(+) lymphocytes and increase in lymphocyte activation between blood, ascites and peritoneal metastases from patients with ovarian cancer. The selective accumulation of CD3(+)CD56(+) population in ascites may be a predictive factor for platinum resistance.

DX5/CD49b-positive T cells are not synonymous with CD1d-dependent NKT cells

NKT cells are typically defined as CD1d-dependent T cells that carry an invariant TCR alpha-chain and produce high levels of cytokines. Traditionally, these cells were defined as NK1.1+ T cells, although only a few mouse strains express the NK1.1 molecule. A popular alternative marker for NKT cells has been DX5, an Ab that detects the CD49b integrin, expressed by most NK cells and a subset of T cells that resemble NKT cells. Interpretation of studies using DX5 as an NKT cell marker depends on how well DX5 defines NKT cells. Using a range of DX5 and other anti-CD49b Abs, we reveal major differences in reactivity depending on which Ab and which fluorochrome are used. The brightest, PE-conjugated reagents revealed that while most CD1d-dependent NKT cells expressed CD49b, they represented only a minority of CD49b+ T cells. Furthermore, CD49b+ T cell numbers were near normal in CD1d-/- mice that are completely deficient for NKT cells. CD1d tetramer- CD49b+ T cells differ from NKT cells by their activation and memory marker expression, tissue distribution, and CD4/CD8 coreceptor profile. Interestingly, both NKT cells and CD1d tetramer- CD49b+ T cells produce cytokines, but the latter are clearly biased toward Th1-type cytokines, in contrast to NKT cells that produce both Th1 and Th2 cytokines. Finally, we demonstrate that expression of CD49b by NKT cells does not dramatically alter with age, contrasting with earlier reports proposing DX5 as a maturation marker for NKT cells. In summary, our data demonstrate that DX5/CD49b is a poor marker for identifying CD1d-dependent NKT cells.

The immunoregulatory role of CD1d-restricted natural killer T cells in disease

Natural killer T (NKT) cells constitute a T cell subpopulation that shares several characteristics with NK cells. NKT cells are characterized by a narrow T cell antigen receptor (TCR) repertoire, recognize glycolipid antigen in the context of the monomorphic CD1d antigen-presenting molecule, and have the unique capacity to rapidly produce large amounts of both T helper (Th) 1 and Th2 cytokines. Important roles of NKT cells have now been demonstrated in the regulation of autoimmune, allergic, antimicrobial, and antitumor immune responses. Here, we review the immunoregulatory role of NKT cells in disease and discuss NKT cell based immunotherapeutic strategies.

CD1d-restricted "NKT" cells and myeloid IL-12 production: an immunological crossroads leading to promotion or suppression of effective anti-tumor immune responses?

CD1d-restricted T cells are remarkable for their unusual ability to respond to self-antigens and to contribute to both immunostimulatory and immunosuppressive responses. Their effects in different cancer models have appeared contradictory; in some cases, they are linked to the generation of effective tumor clearance, and in others, they seem to contribute to suppression of anti-tumor responses. Recent results suggest CD1d-restricted T cells are involved in critical interactions with myeloid dendritic cells (DCs) that can affect the subsequent course of the immune response, and that factors such as the strength of the antigenic signal and the presence or absence of proinflammatory cytokines may determine the outcome of these interactions. In the presence of a strong antigenic signal, CD1d-restricted T cells induced myeloid DCs to secrete interleukin (IL)-12, and these DCs in turn activated naive T cells to secrete Th1 cytokines. When exposed to the weak antigenic stimulus of self-antigens, CD1d-restricted T cells induced DCs to secrete IL-10 but not IL-12, and these DCs failed to stimulate Th1 cytokine production by naive T cells. In contrast, CD1d-restricted T cells that were stimulated by self-antigens in the presence of IL-12 potently secreted interferon-gamma (IFN-gamma) and were among the first lymphocytes to become activated in vivo. Hence, CD1d-restricted T cells may promote or prevent effective anti-tumor responses that are mediated by other lymphocytic effector cells by influencing IL-12 production by myeloid DCs and by their own production of early IFN-gamma in response to IL-12.

Paracrine release of IL-12 stimulates IFN-gamma production and dramatically enhances the antigen-specific T cell response after vaccination with a novel peptide-based cancer vaccine

Interleukin-12 can act as a potent adjuvant for T cell vaccines, but its clinical use is limited by toxicity. Paracrine administration of IL-12 could significantly enhance the response to such vaccines without the toxicity associated with systemic administration. We have developed a novel vaccine delivery system (designated F2 gel matrix) composed of poly-N-acetyl glucosamine that has the dual properties of a sustained-release delivery system and a potent adjuvant. To test the efficacy of paracrine IL-12, we incorporated this cytokine into F2 gel matrix and monitored the response of OT-1 T cells in an adoptive transfer model. Recipient mice were vaccinated with F2 gel/SIINFEKL, F2 gel/SIINFEKL/IL-12 (paracrine IL-12), or F2 gel/SIINFEKL plus systemic IL-12 (systemic IL-12). Systemic levels of IL-12 were lower in paracrine IL-12-treated mice, suggesting that paracrine administration of IL-12 may be associated with less toxicity. However, paracrine administration of IL-12 was associated with an enhanced Ag-specific T cell proliferative and functional response. Furthermore, paracrine IL-12 promoted the generation of a stable, functional memory T cell population and was associated with protection from tumor challenge. To study the mechanisms underlying this enhanced response, wild-type and gene-deficient mice were used. The enhanced immune response was significantly reduced in IFN-gamma(-/-) and IL-12R beta 2(-/-) recipient mice suggesting that the role of IL-12 is mediated, at least in part, by host cells. Collectively, the results support the potential of F2 gel matrix as a vaccine delivery system and suggest that sustained paracrine release of IL-12 has potential clinical application.

Control of NKT cell differentiation by tissue-specific microenvironments

CD1d-restricted Valpha14 NKT cells play an important role in both Th1- and Th2-type immune responses. To determine whether NKT cells develop two functionally distinct subsets that provoke different types of responses, we examined the phenotypes and cellular functions of NK1.1(+) and DX5(+) T cells. We found that both NK1.1(+) and DX5(+) T cells are CD1d-restricted Valpha14 T cells with identical Ag specificities, phenotypes, tissue locations, and functions. Similar to the NK1.1 marker, the DX5 marker (CD49b) is expressed on mature NKT cells in both NK1.1 allele-positive and allele-negative strains. However, when NK1.1(+) and DX5(+) NKT cells isolated from different tissues were compared, we found that thymic and splenic NKT cells differed not only in their cytokine profiles, but also in their phenotype and requirements for costimulatory signals. Thymic NKT cells displayed the phenotype of activated T cells and could be fully activated by TCR ligation. In contrast, splenic NKT cells displayed the phenotype of memory T cells and required a costimulatory signal for activation. Furthermore, the function and phenotype of thymic and splenic NKT cells were modulated by APCs from various tissues that expressed different levels of costimulatory molecules. Modulation of NKT cell function and differentiation may be mediated by synergic effects of costimulatory molecules on the surface of APCs. The results of the present study suggest that the costimulatory signals of tissue-specific APCs are key factors for NKT cell differentiation, and these signals cannot be replaced by anti-CD28 or anti-CD40 ligand Abs.

Immunobiology of haematological malignant disorders: the basis for novel immunotherapy protocols

The immune system is a complex arrangement of cellular interactions that preserve the integrity of a organism by elimination of all elements judged dangerous. However, the development of tumours in immunocompetent patients suggests the existence of an imbalance that favours tumour cells against the immune response. What are the different possibilities for reversing this process to drive an efficient antitumour response? We discuss, focusing on the haematological features, classic immunity (ie, antigen-specific and HLA-restricted immunity). We address the central issues of tumour antigen presentation and recognition and their possible clinical use. Last, we discuss non-HLA-restricted immunity, which does not require the recognition of specific antigens and relies on particular cell populations such as natural killer cells.

Re-evaluating the role of heat-shock protein-peptide interactions in tumour immunity

Early investigations into the immune surveillance of chemically-induced sarcomas led to two important concepts in tumour immunobiology: one, tumour rejection can be elicited by immune recognition of tumour antigens; and two, tumours express unique sets of antigens, which are known as tumour-specific antigens. The pioneering studies of Srivastava and colleagues led to the proposal that heat-shock proteins (HSPs) function as ubiquitous tumour-specific antigens, with the specificity residing in a population of bound peptides that identify the tissue of origin of the HSP. However, recent findings, including new data on the cell biology of peptide generation and trafficking, have called into question the specificity of tumour rejection that is induced by HSPs.

The contribution of NKT cells, NK cells, and other gamma-chain-dependent non-T non-B cells to IL-12-mediated rejection of tumors

IL-12 is a potent cytokine that impairs the growth of several tumors in vivo in natural as well as in therapeutic conditions. Although IL-12 can enhance a number of immunological antitumor mechanisms, including those mediated by NK cells and CTL, recent reports have suggested that the mouse CD1d-restricted V alpha 14-J alpha 18 NKT cell was the essential cell type recruited in most, if not all tumor rejection models, including the B16 melanoma. In this study, we have examined and compared the role of NKT cells, T cells, NK cells, and other non-T non-B cells in the rejection of B16 melanoma cells after exogenous administration of IL-12. Surprisingly, our results failed to confirm a necessary role for NKT cells in this model. Instead, we found that NK cells mediated the rejection of liver metastases, whereas other gamma c-dependent non-T non-B cells, possibly lymphoid dendritic cells, were required for rejection of skin tumors. These findings challenge the view that NKT cells are systematically required for IL-12-mediated rejection of tumors, and instead reveal that a variety of effector pathways can be recruited depending on the tumor microenvironment.

A critical role for natural killer T cells in immunosurveillance of methylcholanthrene-induced sarcomas

Natural killer (NK) T cells initiate potent antitumor responses when stimulated by exogenous factors such as interleukin (IL)-12 or alpha-galactosylceramide (alpha-GalCer), however, it is not clear whether this reflects a physiological role for these cells in tumor immunity. Through adoptive transfer of NK T cells from wild-type to NK T cell-deficient (T cell receptor [TCR] Jalpha281-/-) mice, we demonstrate a critical role for NK T cells in immunosurveillance of methylcholanthrene (MCA)-induced fibrosarcomas, in the absence of exogenous stimulatory factors. Using the same approach with gene-targeted and/or antibody-depleted donor or recipient mice, we have shown that this effect depends on CD1d recognition and requires the additional involvement of both NK and CD8+ T cells. Interferon-gamma production by both NK T cells and downstream, non-NK T cells, is essential for protection, and perforin production by effector cells, but not NK T cells, is also critical. The protective mechanisms in this more physiologically relevant system are distinct from those associated with alpha-GalCer-induced, NK T cell-mediated, tumor rejection. This study demonstrates that, in addition to their importance in tumor immunotherapy induced by IL-12 or alpha-GalCer, NK T cells can play a critical role in tumor immunosurveillance, at least against MCA-induced sarcomas, in the absence of exogenous stimulation.

NKT cells - conductors of tumor immunity?

NKT cells are key players in the regulation of antitumor immunity, particularly in experimental models of tumor immunotherapy, such as IL-12 or alpha-galactosylceramide administration. They may also operate in natural antitumor immunity. NKT cells are best known for their immunosuppressive functions; however, NKT cells interact with a range of other cell types (particularly dendritic cells and NK cells) and the outcome of NKT-cell stimulation depends on these and on the cytokine/co-stimulatory milieu.