Emerging evidence indicates that physiologically relevant thermal stress regulates dendritic cell function

An Integrative Bioorthogonal Nanoengineering Strategy for Dynamically Constructing Heterogenous Tumor Spheroids

Although tumor models have revolutionized perspectives on cancer aetiology and treatment, current cell culture methods remain challenges in constructing organotypic tumor with in vivo-like complexity, especially native characteristics, leading to unpredictable results for in vivo responses. Herein, the bioorthogonal nanoengineering strategy (BONE) for building photothermal dynamic tumor spheroids is developed. In this process, biosynthetic machinery incorporated bioorthogonal azide reporters into cell surface glycoconjugates, followed by reacting with multivalent click ligand (ClickRod) that is composed of hyaluronic acid-functionalized gold nanorod carrying dibenzocyclooctyne moieties, resulting in rapid construction of tumor spheroids. BONE can effectively assemble different cancer cells and immune cells together to construct heterogenous tumor spheroids is identified. Particularly, ClickRod exhibited favorable photothermal activity, which precisely promoted cell activity and shaped physiological microenvironment, leading to formation of dynamic features of original tumor, such as heterogeneous cell population and pluripotency, different maturation levels, and physiological gradients. Importantly, BONE not only offered a promising platform for investigating tumorigenesis and therapeutic response, but also improved establishment of subcutaneous xenograft model under mild photo-stimulation, thereby significantly advancing cancer research. Therefore, the first bioorthogonal nanoengineering strategy for developing dynamic tumor models, which have the potential for bridging gaps between in vitro and in vivo research is presented.

Laser ablation: Heating up the anti-tumor response in the intracranial compartment

Immunotherapies, such as immune checkpoint inhibition (ICI), have had limited success in treating intracranial malignancies. These failures are due partly to the restrictive blood-brain-barrier (BBB), the profound tumor-dependent induction of local and systemic immunosuppression, and immune evasion exhibited by these tumors. Therefore, novel approaches must be explored that aim to overcome these stringent barriers. LITT is an emerging treatment for brain tumors that utilizes thermal ablation to kill tumor cells. LITT provides an additional therapeutic benefit by synergizing with ICI and systemic chemotherapies to strengthen the anti-tumor immune response. This synergistic relationship involves transient disruption of the BBB and local augmentation of immune function, culminating in increased CNS drug penetrance and improved anti-tumor immunity. In this review, we will provide an overview of the challenges facing immunotherapy for brain tumors, and discuss how LITT may synergize with the endogenous anti-tumor response to improve the efficacy of ICI.

Magnetic systems for cancer immunotherapy

Immunotherapy is a rapidly developing area of cancer treatment due to its higher specificity and potential for greater efficacy than traditional therapies. Immune cell modulation through the administration of drugs, proteins, and cells can enhance antitumoral responses through pathways that may be otherwise inhibited in the presence of immunosuppressive tumors. Magnetic systems offer several advantages for improving the performance of immunotherapies, including increased spatiotemporal control over transport, release, and dosing of immunomodulatory drugs within the body, resulting in reduced off-target effects and improved efficacy. Compared to alternative methods for stimulating drug release such as light and pH, magnetic systems enable several distinct methods for programming immune responses. First, we discuss how magnetic hyperthermia can stimulate immune cells and trigger thermoresponsive drug release. Second, we summarize how magnetically targeted delivery of drug carriers can increase the accumulation of drugs in target sites. Third, we review how biomaterials can undergo magnetically driven structural changes to enable remote release of encapsulated drugs. Fourth, we describe the use of magnetic particles for targeted interactions with cellular receptors for promoting antitumor activity. Finally, we discuss translational considerations of these systems, such as toxicity, clinical compatibility, and future opportunities for improving cancer treatment.

Temperature Plays an Essential Regulatory Role in the Tumor Immune Microenvironment

In recent years, emerging immunotherapy has been included in various malignant tumor treatment standards. Temperature has been considered to affect different pathophysiological reactions such as inflammation and cancer for a long time. However, in tumor immunology research, temperature is still rarely considered a significant variable. In this review, we discuss the effects of room temperature, body temperature, and the local tumor temperature on the tumor immune microenvironment from multiple levels and perspectives, and we discuss changes in the body's local and whole-body temperature under tumor conditions. We analyze the current use of ablation treatment-the reason for the opposite immune effect. We should pay more attention to the therapeutic potential of temperature and create a better antitumor microenvironment that can be combined with immunotherapy.

Adjuvant Transgingival Therapy with Visible Light Plus Water-Filtered Infrared-A (VIS + wIRA) in Periodontal Therapy-A Randomized, Controlled, Stratified, Double-Blinded Clinical Trial

The aim of this randomized, controlled, double-blinded clinical trial was to examine the additional healing effect of transgingival visible light and water-filtered infrared-A (VIS + wIRA) in the treatment of periodontitis patients compared with the standard therapy by subgingival instrumentation (SI). Therefore, forty patients with untreated periodontitis received a non-surgical periodontal treatment. Using a split-mouth study design, one quadrant of the upper jaw was randomly either exposed to VIS + wIRA four times for 20 min within two weeks in addition to SI or received only SI. Three and 6 months after intervention, clinical parameters (probing depths (PDs), clinical attachment level, bleeding on probing (BOP), furcation, tooth mobility, plaque control record, and papilla bleeding index) were re-evaluated. In the presence of PD of 4 mm and positive BOP or PD > 4 mm, SI was performed again. Moreover, the patients were asked about their discomfort using a visual analog scale from 1 to 10 for each side of the maxilla. Statistical analysis demonstrated no differences between quadrants at re-evaluation for clinical parameters (p > 0.05) after 3 and 6 months. Concerning pain perception, patients described less pain on the irradiated side (p = 0.016). In the treatment of patients with periodontitis, VIS + wIRA did not show an additional effect on the clinical outcome after 3 and 6 months. Patients described less pain on the irradiated quadrant after treatment.

Hyperthermia Targeting the Tumor Microenvironment Facilitates Immune Checkpoint Inhibitors

Immune checkpoint inhibitors (ICIs) have ushered in a new era of cancer therapy; however, ICIs are only effective in selective patients. The efficacy of ICIs is closely related to the tumor microenvironment. Fever for a long time was thought to directly regulate the immune response, and artificial “fever” from hyperthermia modulates the tumor immune microenvironment by providing danger signals with heat shock proteins (HSPs) as well as subsequent activation of immune systems. Encouraging results have been achieved in preclinical studies focused on potential synergetic effects by combining hyperthermia with ICIs. In this review, we summarized a cluster of immune-related factors that not only make hyperthermia a treatment capable of defending against cancer but also make hyperthermia a reliable treatment that creates a type I-like tumor microenvironment (overexpression of PD-L1 and enrichment of tumor infiltrating lymphocytes) in complementary for the enhancement of the ICIs. Then we reviewed recent preclinical data of the combination regimens involving hyperthermia and ICIs that demonstrated the combined efficacy and illustrated possible approaches to further boost the effectiveness of this combination.

Short-wave enhances mesenchymal stem cell recruitment in fracture healing by increasing HIF-1 in callus

Background

As a type of high-frequency electrotherapy, a short-wave can promote the fracture healing process; yet, its underlying therapeutic mechanisms remain unclear.

Purpose

To observe the effect of Short-Wave therapy on mesenchymal stem cell (MSC) homing and relative mechanisms associated with fracture healing.

Materials and methods

For in vivo study, the effect of Short-Wave therapy to fracture healing was examined in a stabilized femur fracture model of 40 SD rats. Radiography was used to analyze the morphology and microarchitecture of the callus. Additionally, fluorescence assays were used to analyze the GFP-labeled MSC homing after treatment in 20 nude mice with a femoral fracture. For in vitro study, osteoblast from newborn rats simulated fracture site was first irradiated by the Short-Wave; siRNA targeting HIF-1 was used to investigate the role of HIF-1. Osteoblast culture medium was then collected as chemotaxis content of MSC, and the migration of MSC from rats was evaluated using wound healing assay and trans-well chamber test. The expression of HIF-1 and its related factors were quantified by q RT-PCR, ELISA, and Western blot.

Results

Our in vivo experiment indicated that Short-Wave therapy could promote MSC migration, increase local and serum HIF-1 and SDF-1 levels, induce changes in callus formation, and improve callus microarchitecture and mechanical properties, thus speeding up the healing process of the fracture site. Moreover, the in vitro results further indicated that Short-Wave therapy upregulated HIF-1 and SDF-1 expression in osteoblast and its cultured medium, as well as the expression of CXCR-4, β-catenin, F-actin, and phosphorylation levels of FAK in MSC. On the other hand, the inhibition of HIF-1α was significantly restrained by the inhibition of HIF-1α in osteoblast, and it partially inhibited the migration of MSC.

Conclusions

These results suggested that Short-Wave therapy could increase HIF-1 in callus, which is one of the crucial mechanisms of chemotaxis MSC homing in fracture healing.

Modulated Electro-Hyperthermia-Induced Tumor Damage Mechanisms Revealed in Cancer Models

The benefits of high-fever range hyperthermia have been utilized in medicine from the Ancient Greek culture to the present day. Amplitude-modulated electro-hyperthermia, induced by a 13.56 MHz radiofrequency current (mEHT, or Oncothermia), has been an emerging means of delivering loco-regional clinical hyperthermia as a complementary of radiation-, chemo-, and molecular targeted oncotherapy. This unique treatment exploits the metabolic shift in cancer, resulting in elevated oxidative glycolysis (Warburg effect), ion concentration, and electric conductivity. These promote the enrichment of electric fields and induce heat (controlled at 42 °C), as well as ion fluxes and disequilibrium through tumor cell membrane channels. By now, accumulating preclinical studies using in vitro and in vivo models of different cancer types have revealed details of the mechanism and molecular background of the oncoreductive effects of mEHT monotherapy. These include the induction of DNA double-strand breaks, irreversible heath and cell stress, and programmed cells death; the upregulation of molecular chaperones and damage (DAMP) signaling, which may contribute to a secondary immunogenic tumor cell death. In combination therapies, mEHT proved to be a good chemosensitizer through increasing drug uptake and tumor reductive effects, as well as a good radiosensitizer by downregulating hypoxia-related target genes. Recently, immune stimulation or intratumoral antigen-presenting dendritic cell injection have been able to extend the impact of local mEHT into a systemic "abscopal" effect. The complex network of pathways emerging from the published mEHT experiments has not been overviewed and arranged yet into a framework to reveal links between the pieces of the "puzzle". In this paper, we review the mEHT-related damage mechanisms published in tumor models, which may allow some geno-/phenotype treatment efficiency correlations to be exploited both in further research and for more rational clinical treatment planning when mEHT is involved in combination therapies.

Febrile temperature change modulates CD4 T cell differentiation via a TRPV channel-regulated Notch-dependent pathway

Fever is a conserved and prominent response to infection. Yet, the issue of how CD4 T cell responses are modulated if they occur at fever temperatures remains poorly addressed. We have examined the priming of naive CD4 T cells in vitro at fever temperatures, and we report notable fever-mediated modulation of their cytokine commitment. When naive CD4 T cells were primed by plate-bound anti-CD3 and anti-CD28 monoclonal antibodies at moderate fever temperature (39 °C), they enhanced commitment to IL4/5/13 (Th2) and away from IFNg (Th1). This was accompanied by up-regulation of the Th2-relevant transcription factor GATA3 and reduction in the Th1-relevant transcription factor Tbet. Fever sensing by CD4 T cells involved transient receptor potential vanilloid cation channels (TRPVs) since TRPV1/TRPV4 antagonism blocked the febrile Th2 switch, while TRPV1 agonists mediated a Th2 switch at 37 °C. The febrile Th2 switch was IL4 independent, but a γ-secretase inhibitor abrogated it, and it was not found in Notch1-null CD4 T cells, identifying the Notch pathway as a major mediator. However, when naive CD4 T cells were primed via antigen and dendritic cells (DCs) at fever temperatures, the Th2 switch was abrogated via increased production of IL12 from DCs at fever temperatures. Thus, immune cells directly sense fever temperatures with likely complex physiological consequences.

The intersection between immunotherapy and laser interstitial thermal therapy: a multipronged future of neuro-oncology

The rise of immunotherapy (IT) in oncological treatment has greatly improved outcomes in a number of disease states. However, its use in tumors of the central nervous system (CNS) remains limited for multiple reasons related to the unique immunologic tumor microenvironment. As such, it is valuable to consider the intersection of IT with additional treatment methods that may improve access to the CNS and effectiveness of existing IT modalities. One such combination is the pairing of IT with localized hyperthermia (HT) generated through technologies such as laser interstitial thermal therapy (LITT). The wide-ranging immunomodulatory effects of localized and whole-body HT have been investigated for some time. Hyperthermia has demonstrated immunostimulatory effects at the level of tumor cells, immune cells, and the broader environment governing potential immune surveillance. A thorough understanding of these effects as well as the current and upcoming investigations of such in combination with IT is important in considering the future directions of neuro-oncology.

Molecular and biological rationale of hyperthermia as radio- and chemosensitizer

Mild hyperthermia, local heating of the tumour up to temperatures <43 °C, has been clinically applied for almost four decades and has been proven to substantially enhance the effectiveness of both radiotherapy and chemotherapy in treatment of primary and recurrent tumours. Clinical results and mechanisms of action are discussed in this review, including the molecular and biological rationale of hyperthermia as radio- and chemosensitizer as established in in vitro and in vivo experiments. Proven mechanisms include inhibition of different DNA repair processes, (in)direct reduction of the hypoxic tumour cell fraction, enhanced drug uptake, increased perfusion and oxygen levels. All mechanisms show different dose effect relationships and different optimal scheduling with radiotherapy and chemotherapy. Therefore, obtaining the ideal multi-modality treatment still requires elucidation of more detailed data on dose, sequence, duration, and possible synergisms between modalities. A multidisciplinary approach with different modalities including hyperthermia might further increase anti-tumour effects and diminish normal tissue damage.

Role of CINC-1 and CXCR2 receptors on LPS-induced fever in rats

The classic model of fever induction is based on the administration of lipopolysaccharide (LPS) from Gram-negative bacteria in experimental animals. LPS-induced fever results in the synthesis/release of many mediators that assemble an LPS-fever cascade. We have previously demonstrated that cytokine-induced neutrophil chemoattractant (CINC)-1, a Glu-Leu-Arg (ELR) + chemokine, centrally administered to rats, induces fever and increases prostaglandin E₂ in the cerebrospinal fluid. We now attempt to investigate the involvement of CINC-1 and its functional receptor CXCR2 on the fever induced by exogenous and endogenous pyrogens in rats. We also investigated the effect of reparixin, an allosteric inhibitor of CXCR1/CXCR2 receptors, on fever induced by either systemic administration of LPS or intracerebroventricular injection of CINC-1, as well as TNF-α, IL-1β, IL-6, or ET-1, known mediators of febrile response. Our results show increased CINC-1 mRNA expression in the liver, hypothalamus, CSF, and plasma following LPS injection. Moreover, reparixin administered right before CINC-1 or LPS abolished the fever induced by CINC-1 and significantly reduced the response induced by LPS. In spite of these results, reparixin does not modify the fever induced by IL-1β, TNF-α, and IL-6, but significantly reduces ET-1-induced fever. Therefore, it is plausible to suggest that CINC-1 might contribute to LPS-induced fever in rats by activating CXCR2 receptor on the CNS. Moreover, it can be hypothesized that CINC-1 is placed upstream TNF-α, IL-1β, and IL-6 among the prostaglandin-dependent fever-mediator cascade and amidst the prostaglandin-independent synthesis pathway of fever.

Fever-Inspired Immunotherapy Based on Photothermal CpG Nanotherapeutics: The Critical Role of Mild Heat in Regulating Tumor Microenvironment

Although there have been more than 100 clinical trials, CpG-based immunotherapy has been seriously hindered by complications in the immunosuppressive microenvironment of established tumors. Inspired by the decisive role of fever upon systemic immunity, a photothermal CpG nanotherapeutics (PCN) method with the capability to induce an immunofavorable tumor microenvironment by casting a fever-relevant heat (43 °C) in the tumor region is developed. High-throughput gene profile analysis identifies nine differentially expressed genes that are closely immune-related upon mild heat, accompanied by IL-6 upregulation, a pyrogenic cytokine usually found during fever. When treated with intratumor PCN injection enabling mild heating in the tumor region, the 4T1 tumor-bearing mice exhibit significantly improved antitumor immune effects compared with the control group. Superb efficacy is evident from pronounced apoptotic cell death, activated innate immune cells, enhanced tumor perfusion, and intensified innate and adaptive immune responses. This work highlights the crucial role of mild heat in modulating the microenvironment in optimum for improved immunotherapy, by converting the tumor into an in situ vaccine.

Febrile temperature reprograms by redox-mediated signaling the mitochondrial metabolic phenotype in monocyte-derived dendritic cells

Fever-like hyperthermia is known to stimulate innate and adaptive immune responses. Hyperthermia-induced immune stimulation is also accompanied with, and likely conditioned by, changes in the cell metabolism and, in particular, mitochondrial metabolism is now recognized to play a pivotal role in this context, both as energy supplier and as signaling platform. In this study we asked if challenging human monocyte-derived dendritic cells with a relatively short-time thermal shock in the fever-range, typically observed in humans, caused alterations in the mitochondrial oxidative metabolism. We found that following hyperthermic stress (3h exposure at 39°C) TNF-α-releasing dendritic cells undergo rewiring of the oxidative metabolism hallmarked by decrease of the mitochondrial respiratory activity and of the oxidative phosphorylation and increase of lactate production. Moreover, enhanced production of reactive oxygen and nitrogen species and accumulation of mitochondrial Ca²⁺ was consistently observed in hyperthermia-conditioned dendritic cells and exhibited a reciprocal interplay. The hyperthermia-induced impairment of the mitochondrial respiratory activity was (i) irreversible following re-conditioning of cells to normothermia, (ii) mimicked by exposing normothermic cells to the conditioned medium of the hyperthermia-challenged cells, (iii) largely prevented by antioxidant and inhibitors of the nitric oxide synthase and of the mitochondrial calcium porter, which also inhibited release of TNF-α. These observations combined with gene expression analysis support a model based on a thermally induced autocrine signaling, which rewires and sets a metabolism checkpoint linked to immune activation of dendritic cells.

A review of immune therapy in cancer and a question: can thermal therapy increase tumor response?

Immune therapy is a successful cancer treatment coming into its own. This is because checkpoint molecules, adoptive specific lymphocyte transfer and chimeric antigen T-cell (CAR-T) therapy are able to induce more durable responses in an increasing number of malignancies compared to chemotherapy. In addition, immune therapies are able to treat bulky disease, whereas standard cytotoxic therapies cannot treat large tumour burdens. Checkpoint inhibitor monoclonal antibodies are becoming widely used in the clinic and although more complex, adoptive lymphocyte transfer and CAR-T therapies show promise. We are learning that there are nuances to predicting the successful use of the checkpoint inhibitors as well as to specific-antigen adoptive and CAR-T therapies. We are also newly aware of a here-to-fore unrealised natural force, the status of the microbiome. However, despite better understanding of mechanisms of action of the new immune therapies, the best responses to the new immune therapies remain 20-30%. Likely the best way to improve this somewhat low response rate for patients is to increase the patient's own immune response. Thermal therapy is a way to do this. All forms of thermal therapy, from fever-range systemic thermal therapy, to high-temperature HIFU and even cryotherapy improve the immune response pre-clinically. It is time to test the immune therapies with thermal therapy in vivo to test for optimal timing of the combinations that will best enhance tumour response and then to begin to test the immune therapies with thermal therapy in the clinic as soon as possible.

Targeting heat shock factor 1 as an antiviral strategy against dengue virus replication in vitro and in vivo

Fever onset is correlated with viremia in dengue virus (DENV) patients. Heat shock factor 1 (HSF1), a heat stress response host transcription factor, plays a crucial role in regulating multiple cellular functions, as well as the onset of infectious diseases. This study evaluated the role of HSF1 in DENV replication as a means of regulating DENV infection in vitro and in vivo. DENV infection activated HSF1 in both Ca²⁺ and protein kinase A-dependent manners. Inhibiting HSF1 effectively reduced DENV replication, not only in THP-1 cells but also in primary human monocytes. Activated HSF1 contributed to DENV replication by upregulating autophagy-related protein (Atg) 7, as autophagy is crucial for virus replication. Heat stress also activated HSF1, which in turn facilitated DENV replication. Activated HSF1, the increased Atg7, and autophagic induction were founded in the DENV-infected brains and pharmacologically inhibiting HSF1 reduced autophagy, viral protein expression, neuropathy, and mortality. These results provide new insight into HSF1 as a novel host factor for DENV infection through its role in facilitating autophagy-regulated viral replication in the brains.

Fever: Views in Anthroposophic Medicine and Their Scientific Validity

Objective. To conduct a scoping review to characterize how fever is viewed in anthroposophic medicine (AM) and discuss the scientific validity of these views. Methods. Systematic searches were run in Medline, Embase, CAMbase, and Google Scholar. Material from anthroposophic medical textbooks and articles was also used. Data was extracted and interpreted. Results. Most of the anthroposophic literature on this subject is in the German language. Anthroposophic physicians hold a beneficial view on fever, rarely suppress fever with antipyretics, and often use complementary means of alleviating discomfort. In AM, fever is considered to have the following potential benefits: promoting more complete recovery; preventing infection recurrences and atopic diseases; providing a unique opportunity for caregivers to provide loving care; facilitating individual development and resilience; protecting against cancer and boosting the anticancer effects of mistletoe products. These views are discussed with regard to the available scientific data. Conclusion. AM postulates that fever can be of short-term and long-term benefit in several ways; many of these opinions have become evidence-based (though still often not practiced) while others still need empirical studies to be validated, refuted, or modified.

Buthionine sulfoximine, a glutathione depletor, attenuates endotoxic fever and reduces IL-1β and IL-6 level in rats

PURPOSE

The aim of our study was to investigate the effect of buthionine sulfoximine (BSO) - a glutathione depletor - on a course of endotoxic fever and IL-1β and IL-6 production.

MATERIAL AND METHODS

Male Wistar rats were subjected to intraperitoneal injection of lipopolysaccharide (LPS) from E. coli (50μg/kg, ip) to provoke fever. The level of spleen glutathione, plasma interleukin (IL)-1β, IL-6, and deep body temperature (Tb) were measured.

RESULTS

The LPS administration provoked fever (the average Tb was 38.14±0.05°C in NaCl/LPS-treated rats vs 37.10±0.03°C in control, not-treated rats; p<0.001). We observed that LPS injection induced a decrease in spleen glutathione level (7.67±0.92nM/g vs 13.27±0.47nM/g in not-treated rats; p<0.001). Furthermore, the injection of LPS provoked an elevation of plasma IL-1β and IL-6 concentration (from values below the lowest detectable standard in not-treated animals to 199.99±34.89pg/mL and 7500±542.21pg/mL, respectively; p<0.001). Pretreatment with BSO enhanced glutathione decrease in LPS-treated rats (5.05±0.49nM/g), and significantly affected fever (maximal Tb was 37.81±0.07°C in BSO/LPS-treated rats vs 38.76±0.11°C in NaCl/LPS-treated rats). BSO 4h after LPS injection decreased IL-1β and IL-6 gene expression (about 1.5 fold, and 2 fold, respectively). In a consequence we observed a decrease in plasma IL-6 concentration (4h after LPS injection plasma IL-6 was 4167.17±956.54pg/mL in BSO/LPS-treated rats vs 7500±542.21pg/mL in NaCl/LPS-treated rats; p<0.001), and later IL-1β (7h after LPS injection the IL-1β concentration was not detected).

CONCLUSION

Based on these data, we conclude that BSO, in addition to well-known application as an inhibitor of glutathione synthesis, is an antipyretic agent which reduces both IL-1β and IL-6 concentration.

Distinct functional responses to stressors of bone marrow derived dendritic cells from diverse inbred chicken lines

Differences in responses of chicken bone marrow derived dendritic cells (BMDC) to in vitro treatment with lipopolysaccharide (LPS), heat, and LPS + heat were identified. The Fayoumi is more disease resistant and heat tolerant than the Leghorn line. Nitric Oxide (NO) production, phagocytic ability, MHC II surface expression and mRNA expression were measured. NO was induced in BMDC from both lines in response to LPS and LPS + heat stimulation; Fayoumi produced more NO with LPS treatment. Fayoumi had higher phagocytic ability and MHC II surface expression. Gene expression for the heat-related genes BAG3, HSP25, HSPA2, and HSPH1 was strongly induced with heat and few differences existed between lines. Expression for the immune-related genes CCL4, CCL5, CD40, GM-CSF, IFN-γ, IL-10, IL-12β, IL-1β, IL-6, IL-8, and iNOS was highly induced in response to LPS and different between lines. This research contributes to the sparse knowledge of genetic differences in chicken BMDC biology and function.

Transcriptional Targeting of Mature Dendritic Cells with Adenoviral Vectors via a Modular Promoter System for Antigen Expression and Functional Manipulation

To specifically target dendritic cells (DCs) to simultaneously express different therapeutic transgenes for inducing immune responses against tumors, we used a combined promoter system of adenoviral vectors. We selected a 216 bp short Hsp70B' core promoter induced by a mutated, constitutively active heat shock factor (mHSF) 1 to drive strong gene expression of therapeutic transgenes MelanA, BclxL, and IL-12p70 in HeLa cells, as well as in mature DCs (mDCs). As this involves overexpressing mHSF1, we first evaluated the resulting effects on DCs regarding upregulation of heat shock proteins and maturation markers, toxicity, cytokine profile, and capacity to induce antigen-specific CD8(+) T cells. Second, we generated the two-vector-based "modular promoter" system, where one vector contains the mHSF1 under the control of the human CD83 promoter, which is specifically active only in DCs and after maturation. mHSF1, in turn, activates the Hsp70B' core promotor-driven expression of transgenes MelanA and IL-12p70 in the DC-like cell line XS52 and in human mature and hence immunogenic DCs, but not in tolerogenic immature DCs. These in vitro experiments provide the basis for an in vivo targeting of mature DCs for the expression of multiple transgenes. Therefore, this modular promoter system represents a promising tool for future DC-based immunotherapies in vivo.

Mild Heat Treatment Primes Human CD34(+) Cord Blood Cells for Migration Toward SDF-1α and Enhances Engraftment in an NSG Mouse Model

Simple efforts are needed to enhance cord blood (CB) transplantation. We hypothesized that short-term exposure of CD34(+) CB cells to 39.5°C would enhance their response to stromal-derived factor-1 (SDF-1), by increasing lipid raft aggregation and CXCR4 expression, thus leading to enhanced engraftment. Mild hyperthermia (39.5°C) significantly increased the percent of CD34(+) CB that migrated toward SDF-1. This was associated with increased expression of CXCR4 on the cells. Mechanistically, mild heating increased the percent of CD34(+) cells with aggregated lipid rafts and enhanced colocalization of CXCR4 within lipid raft domains. Using methyl-β-cyclodextrin (MβCD), an agent that blocks lipid raft aggregation, it was determined that this enhancement in chemotaxis was dependent upon lipid raft aggregation. Colocalization of Rac1, a GTPase crucial for cell migration and adhesion, with CXCR4 to the lipid raft was essential for the effects of heat on chemotaxis, as determined with an inhibitor of Rac1 activation, NSC23766. Application-wise, mild heat treatment significantly increased the percent chimerism as well as homing and engraftment of CD34(+) CB cells in sublethally irradiated non-obese diabetic severe combined immunodeficiency IL-2 receptor gamma chain d (NSG) mice. Mild heating may be a simple and inexpensive means to enhance engraftment following CB transplantation in patients.

Temperature matters! And why it should matter to tumor immunologists

A major goal of cancer immunology is to stimulate the generation of long-lasting, tumor antigen-specific immune responses that recognize and destroy tumor cells. This article discusses advances in thermal medicine with the potential to improve cancer immunotherapy. Accumulating evidence indicates that survival benefits are accorded to individuals who achieve an increase in body temperature (i.e. fever) following infection. Furthermore, accumulating evidence indicates that physiological responses to hyperthermia impact the tumor microenvironment through temperature-sensitive check-points that regulate tumor vascular perfusion, lymphocyte trafficking, inflammatory cytokine expression, tumor metabolism, and innate and adaptive immune function. Nevertheless, the influence of thermal stimuli on the immune system, particularly the antitum or immune response, remains incompletely understood. In fact, temperature is still rarely considered as a critical variable in experimental immunology. We suggest that more attention should be directed to the role of temperature in the regulation of the immune response and that thermal therapy should be tested in conjunction with immunotherapy as a multi-functional adjuvant that modulates the dynamics of the tumor microenvironment.

Local tumour hyperthermia as immunotherapy for metastatic cancer

Local tumour hyperthermia for cancer treatment is currently used either for ablation purposes as an alternative to surgery or less frequently, in combination with chemotherapy and/or radiation therapy to enhance the effects of those traditional therapies. As it has become apparent that activating the immune system is crucial to successfully treat metastatic cancer, the potential of boosting anti-tumour immunity by heating tumours has become a growing area of cancer research. After reviewing the history of hyperthermia therapy for cancer and introducing methods for inducing local hyperthermia, this review describes different mechanisms by which heating tumours can elicit anti-tumour immune responses, including tumour cell damage, tumour surface molecule changes, heat shock proteins, exosomes, direct effects on immune cells, and changes in the tumour vasculature. We then go over in vivo studies that provide promising results showing that local hyperthermia therapy indeed activates various systemic anti-tumour immune responses that slow growth of untreated tumours. Finally, future research questions that will help bring the use of local hyperthermia as systemic immunotherapy closer to clinical application are discussed.

Fever and the use of paracetamol during IL-2-based immunotherapy in metastatic melanoma

Fever is frequently observed in conjunction with interleukin-2 (IL-2)-based immunotherapy. Traditionally, fever has been regarded as an undesirable side effect and treated with fever-lowering drugs. However, new insights in tumor immunology suggest that elevated temperature may facilitate a more effective antitumor immune response. The purpose of this retrospective study was to examine the potential role of the IL-2-induced fever in melanoma patients treated with or without paracetamol in two consecutive cohorts. One hundred and seventy-nine patients with metastatic melanoma treated with a modified decrescendo regimen of IL-2 and Interferon (IFN) between 2004 and 2010 were retrospectively studied. 87 patients treated before 2007 received paracetamol as part of the treatment schedule, and 92 patients treated after 2007 did not receive paracetamol routinely. Body temperature was analyzed as dichotomized and continuous variables and correlated to objective tumor response and overall survival using logistic regression and Cox proportional hazard analysis. Patients experiencing peak temperature of ≥ 39.5 °C had a median OS of 15.2 months compared to 8.7 months among patients with lower temperatures (P = 0.01). In the multivariate analysis, peak temperature of ≥ 39.5 °C (HR 0.53; P = 0.026) and high mean temperature (HR 0.56; P = 0.004) were independent prognostic factors for improved survival. We suggest high fever as a biomarker for improved survival in melanoma patients treated with IL-2/IFN. The routine use of fever-reducing drugs during immunotherapy can therefore be questioned. More studies are needed to evaluate the role of fever and the use of antipyretics during cytokine-based immunotherapy.

Fever-range temperature modulates activation and function of human dendritic cells stimulated with the pathogenic mould Aspergillus fumigatus

In immunocompromised patients, invasive aspergillosis (IA) is the most frequent disease caused by the pathogenic mould Aspergillus fumigatus. Fever is one of the most common yet nonspecific clinical symptoms of IA. To evaluate the role of hyperthermia in the innate immune response to A. fumigatus in vitro, human monocyte-derived dendritic cells (DCs) were stimulated with germ tubes of A. fumigatus or the fungal cell wall component zymosan at 37°C or 40°C, followed by characterization of specific DC functions. While maturation of DCs was enhanced and DC phagocytic capacity was reduced at 40°C, we observed that DC viability and cytokine release were unaffected. Thus, our results suggest that hyperthermia has substantial impacts on DC function in vitro, which might also influence the course and outcome of IA in immunocompromised patients.

Stressful presentations: mild cold stress in laboratory mice influences phenotype of dendritic cells in naïve and tumor-bearing mice

The ability of dendritic cells (DCs) to stimulate and regulate T cells is critical to effective anti-tumor immunity. Therefore, it is important to fully recognize any inherent factors which may influence DC function under experimental conditions, especially in laboratory mice since they are used so heavily to model immune responses. The goals of this report are to 1) briefly summarize previous work revealing how DCs respond to various forms of physiological stress and 2) to present new data highlighting the potential for chronic mild cold stress inherent to mice housed at the required standard ambient temperatures to influence baseline DCs properties in naïve and tumor-bearing mice. As recent data from our group shows that CD8⁺ T cell function is significantly altered by chronic mild cold stress and since DC function is crucial for CD8⁺ T cell activation, we wondered whether housing temperature may also be influencing DC function. Here we report that there are several significant phenotypical and functional differences among DC subsets in naïve and tumor-bearing mice housed at either standard housing temperature or at a thermoneutral ambient temperature, which significantly reduces the extent of cold stress. The new data presented here strongly suggests that, by itself, the housing temperature of mice can affect fundamental properties and functions of DCs. Therefore differences in basal levels of stress due to housing should be taken into consideration when interpreting experiments designed to evaluate the impact of additional variables, including other stressors on DC function.

Transient receptor potential vanilloid-2 mediates the effects of transient heat shock on endocytosis of human monocyte-derived dendritic cells

Our goal was to investigate the effect of heat shock on human monocyte-derived dendritic cells (DCs) and to dissect the role of thermosensitive transient receptor potential (TRP) channels in the process. We provide evidence that a short heat shock challenge (43 °C) decreased the endocytotic activity of the DCs and that this effect could be alleviated by the RNAi-mediated knockdown of TRPV2 but, importantly, not by the pharmacological (antagonists) or molecular (RNAi) suppression of TRPV1 and TRPV4 activities/levels. Likewise, the heat shock-induced robust membrane currents were selectively and markedly inhibited by TRPV2 "silencing" whereas modulation of TRPV1 and TRPV4 activities, again, had no effect. These intriguing data introduce TRPV2-coupled signaling as a key player in mediating the cellular actions of heat shock on DCs.

The evolutionary significance of depression in Pathogen Host Defense (PATHOS-D)

Given the manifold ways that depression impairs Darwinian fitness, the persistence in the human genome of risk alleles for the disorder remains a much debated mystery. Evolutionary theories that view depressive symptoms as adaptive fail to provide parsimonious explanations for why even mild depressive symptoms impair fitness-relevant social functioning, whereas theories that suggest that depression is maladaptive fail to account for the high prevalence of depression risk alleles in human populations. These limitations warrant novel explanations for the origin and persistence of depression risk alleles. Accordingly, studies on risk alleles for depression were identified using PubMed and Ovid MEDLINE to examine data supporting the hypothesis that risk alleles for depression originated and have been retained in the human genome because these alleles promote pathogen host defense, which includes an integrated suite of immunological and behavioral responses to infection. Depression risk alleles identified by both candidate gene and genome-wide association study (GWAS) methodologies were found to be regularly associated with immune responses to infection that were likely to enhance survival in the ancestral environment. Moreover, data support the role of specific depressive symptoms in pathogen host defense including hyperthermia, reduced bodily iron stores, conservation/withdrawal behavior, hypervigilance and anorexia. By shifting the adaptive context of depression risk alleles from relations with conspecifics to relations with the microbial world, the Pathogen Host Defense (PATHOS-D) hypothesis provides a novel explanation for how depression can be nonadaptive in the social realm, whereas its risk alleles are nonetheless represented at prevalence rates that bespeak an adaptive function.

Tolerogenic dendritic cells that inhibit autoimmune arthritis can be induced by a combination of carvacrol and thermal stress

Tolerogenic dendritic cells (DCs) can induce regulatory T cells and dampen pathogenic T cell responses. Therefore, they are possible therapeutic targets in autoimmune diseases. In this study we investigated whether mouse tolerogenic DCs are induced by the phytonutrient carvacrol, a molecule with known anti-inflammatory properties, in combination with a physiological stress. We show that treatment of DCs with carvacrol and thermal stress led to the mRNA expression of both pro- and anti-inflammatory mediators. Interestingly, treated DCs with this mixed gene expression profile had a reduced ability to activate pro-inflammatory T cells. Furthermore, these DCs increased the proportion of FoxP3⁺ regulatory T cells. In vivo, prophylactic injection of carvacrol-thermal stress treated DCs pulsed with the disease inducing antigen was able to suppress disease in a mouse model of arthritis. These findings suggest that treatment of mouse bone marrow derived DCs with carvacrol and thermal stress induce a functionally tolerogenic DC that can suppress autoimmune arthritis. Herewith carvacrol seems to offer novel opportunities for the development of a dietary based intervention in chronic inflammatory diseases.

Hyperthermia stimulates HIV-1 replication

HIV-infected individuals may experience fever episodes. Fever is an elevation of the body temperature accompanied by inflammation. It is usually beneficial for the host through enhancement of immunological defenses. In cultures, transient non-physiological heat shock (42–45°C) and Heat Shock Proteins (HSPs) modulate HIV-1 replication, through poorly defined mechanisms. The effect of physiological hyperthermia (38–40°C) on HIV-1 infection has not been extensively investigated. Here, we show that culturing primary CD4+ T lymphocytes and cell lines at a fever-like temperature (39.5°C) increased the efficiency of HIV-1 replication by 2 to 7 fold. Hyperthermia did not facilitate viral entry nor reverse transcription, but increased Tat transactivation of the LTR viral promoter. Hyperthermia also boosted HIV-1 reactivation in a model of latently-infected cells. By imaging HIV-1 transcription, we further show that Hsp90 co-localized with actively transcribing provirus, and this phenomenon was enhanced at 39.5°C. The Hsp90 inhibitor 17-AAG abrogated the increase of HIV-1 replication in hyperthermic cells. Altogether, our results indicate that fever may directly stimulate HIV-1 replication, in a process involving Hsp90 and facilitation of Tat-mediated LTR activity.

Fever is a complex reaction triggered in response to pathogen infection. It induces diverse effects on the human body and especially on the immune system. The functions of immune cells are positively affected by fever, helping them to fight infection. Fever consists in a physiological elevation of temperature and in inflammation. While the role of inflammatory molecules on HIV-1 replication has been widely studied, little is known about the direct effect of temperature on viral replication. Here, we report that hyperthermia (39.5°C) boosts HIV-1 replication in CD4+ T cells. In single-cycle infection experiments, hyperthermia increased HIV-1 infection up to 7-fold. This effect was mediated in part by an increased activation of the HIV-1 promoter by the viral protein Tat. Our results also indicate that hyperthermia may help HIV-1 to reactivate from latency. We also show that the Heat Shock Protein Hsp90, which levels are increased at 39.5°C, mediates in a large part the positive effect of hyperthermia on HIV-1 infection. Our work suggests that in HIV-1-infected patients, fever episodes may facilitate viral replication.

Joint effects of febrile acute infection and an interferon-γ polymorphism on breast cancer risk

Background

There is an inverse relationship between febrile infection and the risk of malignancies. Interferon gamma (IFN-γ) plays an important role in fever induction and its expression increases with incubation at fever-range temperatures. Therefore, the genetic polymorphism of IFN-γ may modify the association of febrile infection with breast cancer risk.

Methodology and Principal Findings

Information on potential breast cancer risk factors, history of fever during the last 10 years, and blood specimens were collected from 839 incident breast cancer cases and 863 age-matched controls between October 2008 and June 2010 in Guangzhou, China. IFN-γ (rs2069705) was genotyped using a matrix-assisted laser desorption/ionization time-of-flight mass spectrometry platform. Odds ratios (OR) and 95% confidence intervals (CIs) were calculated using multivariate logistic regression. We found that women who had experienced ≥1 fever per year had a decreased risk of breast cancer [ORs and 95% CI: 0.77 (0.61–0.99)] compared to those with less than one fever a year. This association only occurred in women with CT/TT genotypes [0.54 (0.37–0.77)] but not in those with the CC genotype [1.09 (0.77–1.55)]. The association of IFN-γ rs2069705 with the risk of breast cancer was not significant among all participants, while the CT/TT genotypes were significantly related to an elevated risk of breast cancer [1.32 (1.03–1.70)] among the women with <1 fever per year and to a reduced risk of breast cancer [0.63 (0.40–0.99)] among women with ≥1 fever per year compared to the CC genotype. A marked interaction between fever frequencies and the IFN-γ genotypes was observed (P for multiplicative and additive interactions were 0.005 and 0.058, respectively).

Conclusions

Our findings indicate a possible link between febrile acute infection and a decreased risk of breast cancer, and this association was modified by IFN-γ rs2069705.

Toward establishment of temperature thresholds for immunological impact of heat exposure in humans

There is interest in understanding the health impact of thermal effects as a result of exposure of humans to radiofrequency/microwave (RF/MW) fields. Immune cells and responses are affected by modest changes in temperature and it is important to quantify these effects and establish safety thresholds similar to what has been done with other tissue targets. Since previous summaries of thresholds for thermal damage to normal tissues have not focused much attention to cells of the immune system, this summary highlights recent studies which demonstrate positive and some negative effects of temperature shifts on human immune cells. We emphasise literature reporting adverse immunological endpoints (such as cell damage, death and altered function) and provide the temperature at which these effects were noted. Whereas there have been many in vitro studies of adverse temperature effects on immune cells, there has been limited validation of these temperature effects in vivo. However, data from heat stress/stroke patients do provide some information regarding core temperatures (40°C) at which thermal damage to immunological processes can begin to occur. We conclude that there is considerable need for more quantitative time temperature assessments using relevant animal models, more complete kinetic analyses to determine how long immunological effects persist, and for analysis of whether frequency of exposure has impact on immune function. To date, no attempt to categorise effects by using cumulative thermal dose measurements (e.g. cumulative equivalent minutes at a given temperature) has been conducted for cells or tissues of the immune system, representing a major gap in this field.

Incubation of whole blood at 39°C augments gamma interferon (IFN-γ)-induced protein 10 and IFN-γ responses to Mycobacterium tuberculosis antigens

A rarely challenged dogma in cell-mediated immune (CMI) assays is the incubation temperature, 37°C. Fever augments proinflammatory immune responses in vivo, and the aim of this study was to explore whether incubation at fever-range temperature could increase antigen-specific biomarker responses. We compared CMI responses following incubation of whole blood at 37°C and 39°C. Whole blood was obtained from (i) 34 healthy subjects whose blood was incubated with TB10.4 antigen, present in the Mycobacterium bovis bacillus Calmette-Guérin vaccine and many environmental mycobacteria; (ii) 8 TB patients and 8 controls incubated with Mycobacterium tuberculosis-specific antigens in the QuantiFERON-TB Gold test (QFT-IT); and (iii) from both groups incubated with a T cell mitogen. T cell responses (gamma interferon [IFN-γ]) and responses from antigen-presenting cells (IFN-γ-induced protein 10 [IP-10]) were determined. We further evaluated the effect of adding interleukin-7 (IL-7) and blocking IL-10 during incubation. In TB patients, IFN-γ and IP-10 levels were increased 4.1- and 3.4-fold, respectively, at 39°C incubation (P < 0.001). Similar results were seen after mitogen stimulation. In subjects responding to TB10.4, the effects were less pronounced and significant only for IP-10. Incubation at 39°C increased IP-10 and IFN-γ responsiveness to both antigens and mitogen in persons with baseline or initial low responses. Adding IL-7 and blocking IL-10 augmented the effects in synergy with fever-range temperature. Incubation at fever-range temperature vividly increases CMI responsiveness to antigen stimulation in vitro in tuberculosis patients and may increase the sensitivity of CMI assays.

Fever-range whole body thermotherapy combined with oxaliplatin: a curative regimen in a pre-clinical breast cancer model

PURPOSE

Studies were conducted to test whether fever-range whole body thermal therapy would boost the efficacy of oxaliplatin chemotherapy without substantial toxicity.

MATERIALS AND METHODS

The effect of mild heat (40 degrees C) on oxaliplatin cytotoxicity, cellular uptake, and platinum-DNA adduct formation was studied in vitro using the MTLn3 tumour cell line. In vivo oxaliplatin was administered at various doses and times before, during and after fever-range thermal therapy (6 h at 40 degrees C) to rats bearing an MTLn3 mammary adenocarcinoma. Tumour growth, survival, and toxicity were measured to determine treatment outcome.

RESULTS

Heating halved the oxaliplatin IC-50 dose for MTLn3 cells. Cellular uptake of platinum and platinum adducts increased by 34% and 36%, respectively, with heat. In vivo, 50% of all rats given 10 mg/kg oxaliplatin 24 h before thermal therapy were completely immunologically cured, while a further 11% regressed their primary tumour but ultimately succumbed to metastases, and 17% experienced a limited response with increased survival. The curative response occurred only in a narrow range of doses, with most cures at 10 mg/kg. Thermochemotherapy-treated, but uncured, animals had delayed incidence and slowed growth of metastases. Anti-tumour efficacy was greatest, and toxicity was least, when oxaliplatin was administered 12 or 24 h before fever-range whole body thermal therapy.

CONCLUSIONS

When properly dosed and scheduled, oxaliplatin thermochemotherapy achieved permanent eradication of all primary and metastatic tumours in 50% of animals, seemingly through an immune response. Successful clinical translation of this protocol would yield hitherto unseen cures and substantial improvement in quality of life.

Mild hyperthermia enhances human monocyte-derived dendritic cell functions and offers potential for applications in vaccination strategies

Dendritic cell (DC)-based immunotherapy has been shown to be a promising strategy for anti-cancer therapy. Nevertheless, only a low overall clinical response rate has been observed in vaccinated patients with advanced cancer and therefore methods to improve DC immuno-stimulatory functions are currently under intense investigation. In this respect, we exposed human monocyte-derived DCs to a physiological temperature stress of 40°C for up to 24 h followed by analysis for (i) expression of different heat shock proteins, (ii) survival, (iii) cell surface maturation markers, (iv) cytokine secretion, and (v) migratory capacity. Furthermore, we examined the ability of heat-shocked DCs to prime naïve CD8(+) T cells after loading with MelanA peptide, by transfection with MelanA RNA, or by transduction with MelanA by an adenovirus vector. The results clearly indicate that in comparison to control DCs, which remained at 37°C, heat-treated cells revealed no differences concerning the survival rate or their migratory capacity. However, DCs exposed to thermal stress showed a time-dependent enhanced expression of the immune-chaperone heat shock protein 70A and both an up-regulation of co-stimulatory molecules such as CD80, CD83, and CD86 and of the inflammatory cytokine TNF-α. Moreover, these cells had a markedly improved capacity to prime autologous naïve CD8(+) T cells in vitro in an antigen-specific manner, independent of the method of antigen-loading. Thus, our strategy of heat treatment of DCs offers a promising means to improve DC functions during immune activation which, as a physical method, facilitates straight-forward applications in clinical DC vaccination protocols.

Dendritic cell function at low physiological temperature

Compared with the stable core temperature, the skin temperature is lower and varies depending on ambient temperature and convection conditions. The function of DCs, which are plentiful in the skin at lower physiological temperatures, has not been reported. We show that DC performed some functions normally at 28°C, including phagocytosis and macropinocytosis. TLR-4 signaling via MAPK pathways was delayed at 28°C but reached normal levels, which may explain the observed slower kinetics of stimulated macropinocytosis and TNF production. TLR-4-induced NO production was compromised severely at 28°C. Collagen degradation and migration through matrigel-coated transwell inserts were decreased, but no effect on podosome number or DC migration through noncoated transwell filters was seen. Lowering the temperature differentially regulated functions associated with the role of DCs in adaptive immunity. LPS-induced up-regulation of CD86 was normal; however, CD40 up-regulation was suppressed after TLR-4 stimulation at 28°C. Nonactivated DC processed and presented antigen on MHC class II equally well at 28°C and 37°C. However, DCs that were loaded with antigens and stimulated with TLR ligand at 28°C were poor at activating T cells at 37°C compared with DCs that were activated and loaded with antigen at 37°C.

Tumour infiltrating host cells and their significance for hyperthermia

Much information can be gained by investigating the consequences of hyperthermia on individual cell populations in vitro, however the precise effects of such a therapeutic modality in vivo depend on the tumour microenvironment and the cellular composition therein. Although the direct cytotoxic effects of hyperthermia on tumour tissue can lead to an immediate reduction in tumour volume, long-term benefits to local and distal tumour recurrence will very much depend on the induction of immunity and the capacity of effector cells to traffic to tumours and elicit their cytotoxic functions. The immunological sequelae to hyperthermia are even more important in those instances when large tumour volumes preclude the delivery of appropriate thermal damage. The development of protective anti-tumour immunity requires a plethora of interactions and responses, the vast majority of which can be influenced by temperatures that are consistent with fever-like temperatures (39 degrees -40 degrees C), as well as hyperthermia treatment (<41 degrees C). This article reviews current knowledge relating to the effects of hyperthermia treatment on aspects of the induction and manifestation of immunological responses that are most pertinent to the development and maintenance of protective anti-tumour immunity.

Hypoxia-driven immunosuppression: a new reason to use thermal therapy in the treatment of cancer?

Hypoxia within the tumour microenvironment is correlated with poor treatment outcome after radiation and chemotherapy, and with decreased overall survival in cancer patients. Several molecular mechanisms by which hypoxia supports tumour growth and interferes with effective radiation and chemotherapies are now well established. However, several new lines of investigation are pointing to yet another ominous outcome of hypoxia in the tumour microenvironment: suppression of anti-tumour immune effector cells and enhancement of tumour escape from immune surveillance. This review summarises this important information, and highlights mechanistic data by which hypoxia incapacitates several different types of immune effector cells, enhances the activity of immunosuppressive cells and provides new avenues which help 'blind' immune cells to detect the presence of tumour cells. Finally, we discuss data which indicates that mild thermal therapy, through its physiologically regulated ability to alter vascular perfusion and oxygen tensions within the tumour microenvironment, as well as its ability to enhance the function of some of the same immune effector activities that are inhibited by hypoxia, could be used to rapidly and safely release the tight grip of hypoxia in the tumour microenvironment thereby reducing barriers to more effective immune-based therapies.

Treatment of autoimmune arthritis using RNA interference-modulated dendritic cells

Dendritic cells (DCs) have a dual ability to either stimulate or suppress immunity, which is primarily associated with the expression of costimulatory molecules. Ag-loaded DCs have shown encouraging clinical results for treating cancer and infectious diseases; however, the use of these cells as a means of suppressing immune responses is only recently being explored. Here, we describe the induction of RNA interference through administering short interfering RNA (siRNA) as a means of specifically generating tolerogenic DCs. Knockdown of CD40, CD80, and CD86, prior to loading DCs with the arthritogenic Ag collagen II, led to a population of cells that could effectively suppress onset of collagen-induced arthritis. Maximum benefits were observed when all three genes were concurrently silenced. Disease suppression was associated with inhibition of collagen II-specific Ab production and suppression of T cell recall responses. Downregulation of IL-2, IFN-gamma, TNF-alpha, and IL-17 and increased FoxP3(+) cells with regulatory activity were observed in collagen-induced arthritis mice treated with siRNA-transfected DCs. Collectively, these data support the use of ex vivo gene manipulation in DCs using siRNA to generate tailor-made tolerogenic vaccines for treating autoimmunity.

Increased intracellular, cell surface, and secreted inducible heat shock protein 70 responses are triggered during the monocyte to dendritic cell (DC) transition by cytokines independently of heat stress and infection and may positively regulate DC growth

Physiologic triggers and functional consequences of endogenous heat shock protein (HSP) responses in dendritic cells (DC) are poorly defined. In this study, we show that even in the absence of heat stress and infection, a specific cohort of DC/proinflammatory cytokines (IL-4-IL-13/IL-6/GM-CSF) institutes an enhanced inducible (i)HSP70 intracellular and extracellular response in human monocyte-derived DC, especially during the monocyte to DC transition. Interestingly, whereas heat stress alone initiated an intracellular iHSP70 response in monocyte DC precursors, it did not promote cell surface or secreted iHSP70 responses, both of which were induced by cytokines independently of heat. The cytokine-induced iHSP70 response, which did not occur in lymphocytes, or monocytes-macrophages generated with M-CSF, was instituted within 48 h of cytokine exposure, and peaked upon commitment to DC growth at 72 h. Although a return to baseline levels was noted after this period, a distinct rise in iHSP70 occurred again during terminal DC maturation. Chemical inhibition of the iHSP70 response with either triptolide or KNK-437 was coupled with inhibition of DC differentiation and yielded cells displaying features of monocytes-macrophages. Exogenously supplied riHSP70 amplified events associated with cytokine-advanced DC differentiation/maturation, most notably the up-regulation of antiapoptotic proteins (Bcl-x(L)). Engaging the HSP receptor CD40 with CD40L produced identical results as extracellular riHSP70, and, moreover, an enhanced iHSP70 response. Thus, distinct iHSP70 and HSP receptor-mediated responses are triggered by cytokines irrespective of heat stress and infection in monocyte-derived DC and may function to positively regulate monocyte-derived DC, especially during critical periods of their growth.

Hypothermia and surgery: immunologic mechanisms for current practice

OBJECTIVE

To examine cellular and immunologic mechanisms by which intraoperative hypothermia affects surgical patients.

SUMMARY BACKGROUND DATA

Avoidance of perioperative hypothermia has recently become a focus of attention as an important quality performance measure, aimed at optimizing the care of surgical patients. Anesthetized surgical patients are particularly at risk for hypothermia, which has been directly linked to the development of sequelae, such as coagulopathy, infection, morbid myocardial events, and death after surgery. However, many of the underlying immunologic mechanisms remain unclear.

METHODS

Venous blood samples from healthy volunteers were exposed for up to 4 hours to various temperatures following the addition of a 1 ng/mL lipopolysaccharide challenge. Innate immune function, assessed by the ability of monocytes to present antigen and coordinate cytokine release, was determined by qualitative and quantitative measurements of HLA-DR surface expression 2 hours following incubation, and proinflammatory tumor necrosis factor-alpha (TNF-alpha) and anti-inflammatory (IL-10) cytokine release in the first 4 hours.

RESULTS

Monocyte incubation at hypothermic temperatures (34 degrees C) reduced HLA-DR surface expression, delayed TNF-alpha clearance, and increased IL-10 release. Conversely, hyperthermia (40 degrees C) increased monocyte antigen presentation and resulted in rapid decay of TNF-alpha. However, IL-10 release was also increased. Normothermia (37 degrees C) attenuated IL-10 release following the initial proinflammatory surge.

CONCLUSION

Hypothermia exerts multiple effects at the cellular level, which impair innate immune function, and are associated with increased septic complications and mortality. These findings provide a physiological basis for perioperative temperature monitoring, which is a valid surgical performance measure that can be used to reduce surgical complications associated with avoidable hypothermia.

"Danger" conditions increase sulfamethoxazole-protein adduct formation in human antigen-presenting cells

Antigen-presenting cells (APC) are thought to play an important role in the pathogenesis of drug-induced immune reactions. Various pathological factors can activate APC and therefore influence the immune equilibrium. It is interesting that several diseases have been associated with an increased rate of drug allergy. The aim of this project was to evaluate the impact of such "danger signals" on sulfamethoxazole (SMX) metabolism in human APC (peripheral blood mononuclear cells, Epstein-Barr virus-modified B lymphocytes, monocyte-derived dendritic cells, and two cell lines). APC were incubated with SMX (100 microM-2 mM; 5 min-24 h), in the presence of pathological factors: bacterial endotoxins (lipopolysaccharide and staphylococcal enterotoxin B), flu viral proteins, cytokines [interleukin (IL)-1beta, IL-6, IL-10; tumor necrosis factor-alpha; interferon-gamma; and transforming growth factor-beta], inflammatory molecules (prostaglandin E2, human serum complement, and activated protein C), oxidants (buthionine sulfoximine and H(2)O(2)), and hyperthermia (37.5-39.5 degrees C). Adduct formation was evaluated by enzyme-linked immunosorbent assay and confocal microscopy. SMX-protein adduct formation was time- and concentration-dependent for each cell type tested, in both physiological and danger conditions. A danger environment significantly increased the formation of SMX-protein adducts and significantly shortened the delay for their detection. An additive effect was observed with a combination of danger signals. Dimedone (chemical selectively binding cysteine sulfenic acid) and antioxidants decreased both baseline and danger-enhanced SMX-adduct formation. Various enzyme inhibitors were associated with a significant decrease in SMX-adduct levels, with a pattern varying depending on the cell type and the culture conditions. These results illustrate that danger signals enhance the formation of intracellular SMX-protein adducts in human APC. These findings might be relevant to the increased frequency of drug allergy in certain disease states.

Frontiers in biotransport: water transport and hydration

Biotransport, by its nature, is concerned with the motions of molecules in biological systems while water remains as the most important and the most commonly studied molecule across all disciplines. In this review, we focus on biopreservation and thermal therapies from the perspective of water, exploring how its molecular motions, properties, kinetic, and thermodynamic transitions govern biotransport phenomena and enable preservation or controlled destruction of biological systems.

Frontiers in Biotransport: Water Transport and Hydration

Biotransport, by its nature, is concerned with the motions of molecules in biological systems while water remains as the most important and the most commonly studied molecule across all disciplines. In this review, we focus on biopreservation and thermal therapies from the perspective of water, exploring how its molecular motions, properties, kinetic, and thermodynamic transitions govern biotransport phenomena and enable preservation or controlled destruction of biological systems.