On Analyzing How the Th1/Th2 Phenotype of an Immune Response Is Determined: Classical Observations Must Not Be Ignored

A Four-Gene Panel for the Prediction of Prognosis and Immune Cell Enrichment in Gliomas

BACKGROUNDS

Gliomas is a deadly disease without effective therapy. Although immunotherapy has provided novel choices for glioma treatment, the curative efficacy is unsatisfactory due to the complex immune micro-environment and the heterogeneity of the disease. Therefore, it is urgent to identify effective biomarkers and therapeutic targets.

METHODS

Overall survival, gene ontology (GO), Kyoto Encyclopedia of Genes, and Genomes (KEGG) enrichment analysis, Gene Set Enrichment Analysis (GSEA) and immune infiltration were analyzed by bioinformatics software with The Cancer Genome Atlas (TCGA) database.

RESULTS

Based on the TCGA database and protein-protein interaction (PPI) analysis revealed a four-gene panels [DNA topoisomerase II alpha (TOP2A); ribonucleotide reductase regulatory subunit M2 (RRM2); kinesin family member 20 A (KIF20A) and DLG associated protein 5 (DLGAP5)], which correlated with poor prognosis, including overall survival (OS), disease specific survival (DSS) and progress free interval (PFI), mitosis, cell cycle, Th2 cells and macrophages enrichment. The four-gene panels correlates with the biomarkers of Th2 cells, macrophages tumor-associated macrophages (TAMs) and the immune checkpoint molecules in gliomas.

CONCLUSION

The four-gene panels represented a novel prognostic indicator and potential therapeutic target for the treatment of glioma. In addition, the four-gene panels might contribute to enhance the efficacy of immunotherapy in glioma.

The Th1/Th2 paradigm: A misrepresentation of helper T cell plasticity

For decades, the Th1/2 paradigm has been used to classify immune responses as either Th1 or Th2-biased. However, in recent years, a staggering amount of evidence has emerged to support rejection of the classical Th1/Th2 paradigm, such as the discoveries of new helper T cell subsets, helper T cell plasticity and protective mixed-Th1/Th2 responses. This opinion piece investigates the shortcomings of classical Th1/Th2 paradigm in the context of recent works, with the goal of facilitating the development of newer models to represent the diversity of Th cells.

Breast Cancer Immune Landscape: Interplay Between Systemic and Local Immunity

Breast cancer (BC) is one of the most common malignancies in women worldwide. Numerous studies in immuno-oncology and successful trials of immunotherapy have demonstrated the causal role of the immune system in cancer pathogenesis. The interaction between the tumor and the immune system is known to have a dual nature. Despite cytotoxic lymphocyte activity against transformed cells, a tumor can escape immune surveillance and leverage chronic inflammation to maintain its own development. Research on antitumor immunity primarily focuses on the role of the tumor microenvironment, whereas the systemic immune response beyond the tumor site is described less thoroughly. Here, a comprehensive review of the formation of the immune profile in breast cancer patients is offered. The interplay between systemic and local immune reactions as self-sustaining mechanism of tumor progression is described and the functional activity of the main cell populations related to innate and adaptive immunity is discussed. Additionally, the interaction between different functional levels of the immune system and their contribution to the development of the pro- or anti-tumor immune response in BC is highlighted. The presented data can potentially inform the development of new immunotherapy strategies in the treatment of patients with BC.

Screening for lipid nanoparticles that modulate the immune activity of helper T cells towards enhanced antitumour activity

Lipid nanoparticles (LNPs) can be designed to potentiate cancer immunotherapy by promoting their uptake by antigen-presenting cells, stimulating the maturation of these cells and modulating the activity of adjuvants. Here we report an LNP-screening method for the optimization of the type of helper lipid and of lipid-component ratios to enhance the delivery of tumour-antigen-encoding mRNA to dendritic cells and their immune-activation profile towards enhanced antitumour activity. The method involves screening for LNPs that enhance the maturation of bone-marrow-derived dendritic cells and antigen presentation in vitro, followed by assessing immune activation and tumour-growth suppression in a mouse model of melanoma after subcutaneous or intramuscular delivery of the LNPs. We found that the most potent antitumour activity, especially when combined with immune checkpoint inhibitors, resulted from a coordinated attack by T cells and NK cells, triggered by LNPs that elicited strong immune activity in both type-1 and type-2 T helper cells. Our findings highlight the importance of optimizing the LNP composition of mRNA-based cancer vaccines to tailor antigen-specific immune-activation profiles.

An overview of the regulatory role of annexin A1 in the tumor microenvironment and its prospective clinical application (Review)

Although annexin A1 (ANXA1), a 37 kDa phospholipid‑binding anti‑inflammatory protein expressed in various tissues and cell types, has been investigated extensively for its regulatory role in cancer biology, studies have mainly focused on its intracellular role. However, cancer cells and stromal cells expressing ANXA1 have the ability to transmit signals within the tumor microenvironment (TME) through autocrine, juxtacrine, or paracrine signaling. This bidirectional crosstalk between cancer cells and their environment is also crucial for cancer progression, contributing to uncontrolled tumor proliferation, invasion, metastasis and resistance to therapy. The present review explored the important role of ANXA1 in regulating the cell‑specific crosstalk between various compartments of the TME and analyzed the guiding significance of the crosstalk effects in promotion or suppressing cancer progression in the development of cancer treatments. The literature shows that ANXA1 is critical for the regulation of the TME, indicating that ANXA1 signaling between cancer cells and the TME is a potential therapeutic target for the development of novel therapeutic approaches for impeding cancer development.

Development of a nano-emulsion based multivalent protein subunit vaccine against Pseudomonas aeruginosa

Pseudomonas aeruginosa (Pa) is an opportunistic bacterial pathogen responsible for severe hospital acquired infections in immunocompromised and elderly individuals. Emergence of increasingly drug resistant strains and the absence of a broad-spectrum prophylactic vaccine against both T3SA+ (type III secretion apparatus) and ExlA+/T3SA- Pa strains worsen the situation in a post-pandemic world. Thus, we formulated a candidate subunit vaccine (called ExlA/L-PaF/BECC/ME) against both Pa types. This bivalent vaccine was generated by combining the C-terminal active moiety of exolysin A (ExlA) produced by non-T3SA Pa strains with our T3SA-based vaccine platform, L-PaF, in an oil-in-water emulsion. The ExlA/L-PaF in ME (MedImmune emulsion) was then mixed with BECC438b, an engineered lipid A analogue and a TLR4 agonist. This formulation was administered intranasally (IN) to young and elderly mice to determine its potency across a diverse age-range. The elderly mice were used to mimic the infection seen in elderly humans, who are more susceptible to serious Pa disease compared to their young adult counterparts. After Pa infection, mice immunized with ExlA/L-PaF/BECC/ME displayed a T cell-mediated adaptive response while PBS-vaccinated mice experienced a rapid onset inflammatory response. Important genes and pathways were observed, which give rise to an anti-Pa immune response. Thus, this vaccine has the potential to protect aged individuals in our population from serious Pa infection.

A Plausible Framework Reveals Potential Similarities in the Regulation of Immunity against Some Cancers and Some Infectious Agents: Implications for Prevention and Treatment

Different frameworks, which are currently employed to understand how immune responses are regulated, can account for different observations reported in the classical literature. I have argued that the predominant frameworks, employed over the last two/three decades to analyze the circumstances that determine whether an immune response is generated or this potential is ablated, and that determine the class of immunity an antigen induces, are inconsistent with diverse classical observations. These observations are "paradoxical" within the context of these frameworks and, consequently, tend to be ignored by most contemporary researchers. One such observation is that low and high doses of diverse types of antigen result, respectively, in cell-mediated and IgG antibody responses. I suggest these paradoxes render these frameworks implausible. An alternative framework, The Threshold Hypothesis, accounts for the paradoxical observations. Some frameworks are judged more plausible when found to be valuable in understanding findings in fields beyond their original compass. I explore here how the Threshold Hypothesis, initially based on studies with chemically well-defined and "simple antigens", most often a purified protein, can nevertheless shed light on diverse classical and more recent observations in the fields of immunity against cancer and against infectious agents, thus revealing common, immune mechanisms. Most cancers and some pathogens are best contained by cell-mediated immunity. The success of the Threshold Hypothesis has encouraged me to employ it as a basis for proposing strategies to prevent and to treat cancer and those infectious diseases caused by pathogens best contained by a cell-mediated attack.

Coal-Derived Humic Substances: Insight into Chemical Structure Parameters and Biomedical Properties

An investigation was carried out on humic substances (HSs) isolated from the coal of the Kansk-Achinsk basin (Krasnoyarsk Territory, Russia). The coal HSs demonstrate the main parameters of molecular structure inherent to this class of natural compounds. An assessment was performed for the chemical, microbiological, and pharmacological safety parameters, as well as the biological efficacy. The HS sample meets the safety requirements in microbiological purity, toxic metals content (lead, cadmium, mercury, arsenic), and radionuclides. The presence of 11 essential elements was determined. The absence of general, systemic toxicity, cytotoxicity, and allergenic properties was demonstrated. The coal HS sample was classified as a Class V hazard (low danger substances). High antioxidant and antiradical activities and immunotropic and cytoprotective properties were identified. The ability of the HS to inhibit hydroxyl radicals and superoxide anion radicals was revealed. Pronounced actoprotective and nootropic activities were also demonstrated in vivo. Intragastric administration of the HS sample resulted in the improvement of physical parameters in mice as assessed by the "swim exhaustion" test. Furthermore, intragastric administration in mice with cholinergic dysfunction led to a higher ability of animals with scopolamine-induced amnesia to form conditioned reflexes. These findings suggest that the studied HS sample is a safe and effective natural substance, making it suitable for use as a dietary bioactive supplement.

Targeting MELK improves PD-1 blockade efficiency in cervical cancer via enhancing antitumor immunity

The balance between T helper 1 (Th1) and T helper 2 (Th2) has a critical function in determining intratumoral immune response and anti-PD-1 immunotherapy. The level of maternal embryonic leucine zipper kinase (MELK) is reported to correlate with infiltration of immune cells in cancers, but the underlying molecular mechanism is not clarified. In the present study, we aimed to elucidate the potential function of MELK in cervical cancer. We found that MELK was upregulated and played an oncogenic role in cervical cancer. MELK overexpression shifted Th1/Th2 balance toward Th2 predisposition in mouse cervical tumors in vivo and naive T cells from human PBMCs in vitro, whereas MELK knockdown exhibited opposite effects. MELK overexpression activated NF-κB signaling and promoted IL-6 secretion by cervical cancer cells. Depletion of IL-6 by neutralization antibodies abrogated the influence of MELK on Th1/Th2 balance. In addition, MELK modulated the antitumor activity of cytotoxic CD8+ T cells in cervical tumors, but depletion of Th2 cells by IL-4 neutralization abrogated this effect. Finally, MELK overexpression conferred tolerance to PD-1 blockade in cervical tumors, whereas targeting MELK by OTSSP167 significantly enhanced PD-1 blockade efficiency. Our data elucidated a novel role of MELK in regulating Th1/Th2 balance and anti-PD-1 immunotherapy in cervical cancer.

Antibodies as clinical tools for tuberculosis

Tuberculosis (TB) is a leading cause of morbidity and mortality worldwide. Global research efforts to improve TB control are hindered by insufficient understanding of the role that antibodies play in protective immunity and pathogenesis. This impacts knowledge of rational and optimal vaccine design, appropriate diagnostic biomarkers, and development of therapeutics. Traditional approaches for the prevention and diagnosis of TB may be less efficacious in high prevalence, remote, and resource-poor settings. An improved understanding of the immune response to the causative agent of TB, Mycobacterium tuberculosis (Mtb), will be crucial for developing better vaccines, therapeutics, and diagnostics. While memory CD4+ T cells and cells and cytokine interferon gamma (IFN-g) have been the main identified correlates of protection in TB, mounting evidence suggests that other types of immunity may also have important roles. TB serology has identified antibodies and functional characteristics that may help diagnose Mtb infection and distinguish between different TB disease states. To date, no serological tests meet the World Health Organization (WHO) requirements for TB diagnosis, but multiplex assays show promise for improving the sensitivity and specificity of TB serodiagnosis. Monoclonal antibody (mAb) therapies and serum passive infusion studies in murine models of TB have also demonstrated some protective outcomes. However, animal models that better reflect the human immune response to Mtb are necessary to fully assess the clinical utility of antibody-based TB prophylactics and therapeutics. Candidate TB vaccines are not designed to elicit an Mtb-specific antibody response, but evidence suggests BCG and novel TB vaccines may induce protective Mtb antibodies. The potential of the humoral immune response in TB monitoring and control is being investigated and these studies provide important insight into the functional role of antibody-mediated immunity against TB. In this review, we describe the current state of development of antibody-based clinical tools for TB, with a focus on diagnostic, therapeutic, and vaccine-based applications.

Relapsing/remitting multiple sclerosis: A speculative model and its implications for a novel treatment

The clinical pattern in relapsing/remitting multiple sclerosis may be accounted for if an autoreactive immune response can transition back and forth between inflammatory, pathogenic, and non-inflammatory, non-pathogenic modes. Such 'back-and-forth' immune responses are rare. I speculate how such back-and-forth immune responses may arise. Understanding the nature of these different modes, and what controls their mutual transition, may help in designing strategies to favour the nonpathogenic mode, thus constituting treatment. Antigen dose is known to be critical in determining the class/subclass of primary immune responses. Observations have led us to suggest the level of antigen also similarly influences the class/subclass of on-going immune responses. I propose the relapsing, inflammatory and the remitting modes are respectively sustained by relatively low and high amounts of the responsible autoantigens, as is the case, for example, for Th1 and Th2 responses to foreign antigens. In addition, I propose more self-antigens are released during an inflammatory than during a remitting mode. The decrease in the amount of antigen released, as the response transitions from an inflammatory to a remitting mode, results in time in a decreased level of antigen and so the response again evolves towards the inflammatory mode. The inflammatory mode then leads to an increased release of antigen and so, in time, to remission. This model thus explains the transition between different modes. I outline non-invasive, testable predictions of the hypothesis. If confirmed, it may be ethical to examine whether the non-inflammatory mode can be sustained by administering myelin antigens during the remitting phase.

What Determines the Class of Immunity an Antigen Induces? A Foundational Question Whose Rational Consideration Has Been Undermined by the Information Overload

Activated CD4 T helper cells are required to activate B cells to produce antibody and CD8 T cells to generate cytotoxic T lymphocytes. In the absence of such help, antigens inactivate B cells and CD8 T cells. Thus, the activation or inactivation of CD4 T cells determines whether immune responses are generated, or potentially ablated. Most consider that the activation of CD4 T cells requires an antigen-dependent signal, signal 1, as well as a critical costimulatory signal, initiated when a pattern recognition receptor (PRR) engages with a danger- or pathogen-associated molecular pattern (DAMP or PAMP). Most also envisage that the nature of the DAMP/PAMP signal determines the Th subset predominantly generated and so the class of immunity predominantly induced. I argue that this framework is implausible as it is incompatible with diverse observations of the variables of immunization affecting the class of immunity induced. An alternative framework, the threshold hypothesis, posits that different levels of antigen mediated CD4 T cell interactions lead to the generation of different Th subsets and so different classes of immunity, that it is compatible with these observations. This alternative supports a rational approach to preventing and treating diverse clinical conditions associated with infectious disease and, more speculatively, with cancer.

Experimental evidence of parasite-induced behavioural alterations modulated by food availability in wild capuchin monkeys

In disease dynamics, host behaviour can both determine the quantity of parasites a host is exposed to, and be a consequence of infection. Observational and experimental studies in non-human primates have consistently found that parasitic infections result in less movement and reduced foraging, which was interpreted as an adaptive response of the host to counter infection. Variation in host nutritional condition may add complexity to the infection-behaviour relationship, and its influence may shed light on its significance. To experimentally evaluate how host activity and social relationships are affected by the interaction of parasitism and nutrition, during two years we manipulated food availability by provisioning bananas, and helminth infections by applying antiparasitic drugs, in two groups of wild black capuchin monkeys (Sapajus nigritus) in Iguazú National Park, Argentina. We collected faecal samples to determine the intensity of helminthic infections, as well as data on behaviour and social proximity. Individuals with unmanipulated helminth burdens foraged less than dewormed individuals only when food provisioning was low. Resting time was increased when capuchins were highly provisioned, but it did not vary according to the antiparasitic treatment. Proximity associations to other group members were not affected by the antiparasitic treatment. This is the first experimental evidence of a modulating effect of food availability on the influence of helminth infection on activity in wild primates. The findings are more consistent with an impact on host behaviour due to the debilitating effect caused by parasites than with an adaptive response to help fight infections.

The Role of Microbiota-Derived Vitamins in Immune Homeostasis and Enhancing Cancer Immunotherapy

Not all cancer patients who receive immunotherapy respond positively and emerging evidence suggests that the gut microbiota may be linked to treatment efficacy. Though mechanisms of microbial contributions to the immune response have been postulated, one likely function is the supply of basic co-factors to the host including selected vitamins. Bacteria, fungi, and plants can produce their own vitamins, whereas humans primarily obtain vitamins from exogenous sources, yet despite the significance of microbial-derived vitamins as crucial immune system modulators, the microbiota is an overlooked source of these nutrients in humans. Microbial-derived vitamins are often shared by gut bacteria, stabilizing bioenergetic pathways amongst microbial communities. Compositional changes in gut microbiota can affect metabolic pathways that alter immune function. Similarly, the immune system plays a pivotal role in maintaining the gut microbiota, which parenthetically affects vitamin biosynthesis. Here we elucidate the immune-interactive mechanisms underlying the effects of these microbially derived vitamins and how they can potentially enhance the activity of immunotherapies in cancer.

Insight into SARS-CoV-2 Omicron variant immune escape possibility and variant independent potential therapeutic opportunities

The Omicron, the latest variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was first detected in November 2021 in Botswana, South Africa. Compared to other variants of SARS-CoV-2, the Omicron is the most highly mutated, with 50 mutations throughout the genome, most of which are in the spike (S) protein. These mutations may help the Omicron to evade host immunity against the vaccine. Epidemiological studies suggest that Omicron is highly infectious and spreads rapidly, but causes significantly less severe disease than the wild-type strain and the other variants of SARS-CoV-2. With the increased transmissibility and a higher rate of re-infection, Omicron has now become a dominant variant worldwide and is predicted to be able to evade vaccine-induced immunity. Several clinical studies using plasma samples from individuals receiving two doses of US Food and Drugs Administration (FDA)-approved COVID-19 vaccines have shown reduced humoral immune response against Omicron infection, but T cell-mediated immunity was well preserved. In fact, T cell-mediated immunity protects against severe disease, and thus the disease caused by Omicron remains mild. In this review, I surveyed the current status of Omicron variant mutations and mechanisms of immune response in the context of immune escape from COVID-19 vaccines. I also discuss the potential implications of therapeutic opportunities that are independent of SARS-CoV-2 variants, including Omicron. A better understanding of vaccine-induced immune responses and variant-independent therapeutic interventions that include potent antiviral, antioxidant, and anti-cytokine activities may pave the way to reducing Omicron-related COVID-19 complications, severity, and mortality. Collectively, these insights point to potential research gaps and will aid in the development of new-generation COVID-19 vaccines and antiviral drugs to combat Omicron, its sublineages, or upcoming new variants of SARS-CoV-2.

A Framework for Understanding Maternal Immunity

This is an alternative and controversial framing of the data relevant to maternal immunity. It argues for a departure from classical theory to view, interrogate and interpret existing data.

The Problem of Host and Pathogen Genetic Variability for Developing Strategies of Universally Efficacious Vaccination against and Personalised Immunotherapy of Tuberculosis: Potential Solutions?

Rational vaccination against and immunotherapy of any infectious disease requires knowledge of how protective and non-protective immune responses differ, and how immune responses are regulated, so their nature can be controlled. Strong Th1 responses are likely protective against M tuberculosis. Understanding how immune class regulation is achieved is pertinent to both vaccination and treatment. I argue that variables of infection, other than PAMPs, primarily determine the class of immunity generated. The alternative, non-PAMP framework I favour, allows me to propose strategies to achieve efficacious vaccination, transcending host and pathogen genetic variability, to prevent tuberculosis, and personalised protocols to treat disease.

The hallmark and crosstalk of immune cells after intracerebral hemorrhage: Immunotherapy perspectives

Intracerebral hemorrhage (ICH) is one of the most dangerous types of strokes with a high morbidity and mortality rate. Currently, the treatment of ICH is not well developed, mainly because its mechanisms are still unclear. Inflammation is one of the main types of secondary injury after ICH and catalyzes the adverse consequences of ICH. A large number of immune cells are involved in neuroinflammation, such as microglia, astrocytes, oligodendrocytes, lymphocytes, macrophages, and neutrophils. Nevertheless, the characteristics and crosstalk of immune cells have not been fully elucidated. In this review, we endeavor to delve into the respective characteristics of immune cells and their interactions in neuroimmune inflammation, and further elucidate favorable immunotherapeutic approaches regarding ICH, and finally present an outlook.

Induction of a strong and long-lasting neutralizing immune response by dPreS1-TLR2 agonist nanovaccine against hepatitis B virus

Hepatitis B virus remains a major medical burden with more than 250 million chronically infected patients worldwide and 900,000 deaths each year, due to the disease progression towards severe complications (cirrhosis, hepatocellular carcinoma). Despite the availability of a prophylactic vaccine, this infection is still pandemic in Western Pacific and African regions, where around 6% of the adult population is infected. Among novel anti-HBV strategies, innovative drug delivery systems, such as nanoparticle platforms to deliver vaccine antigens or therapeutic molecules have been investigated. Here, we developed polylactic acid-based biodegradable nanoparticles as an innovative and efficient vaccine. They are twice functionalized by (i) the entrapment of Pam₃CSK₄, an immunomodulator and ligand to Toll-Like-Receptor 1/2, and by (ii) the adsorption/coating of myristoylated (2-48) derived PreS1 from the HBV surface antigen, identified as the major viral attachment site on hepatocytes. We demonstrate that such formulations mimic HBV virion with an efficient peptide recognition by the immune system, and elicit potent and durable antibody responses in naive mice during at least one year. We also show that the most efficient in vitro viral neutralization was observed with NP-Pam₃CSK₄-dPreS1 sera. The immunogenicity of the derived HBV antigen is modulated by the likely synergistic action of both the dPreS1 coated nanovector and the adjuvant moiety. This formulation represents a promising vaccine alternative to fight HBV infection.

Boolean modeling reveals that cyclic attractors in macrophage polarization serve as reservoirs of states to balance external perturbations from the tumor microenvironment

Cyclic attractors generated from Boolean models may explain the adaptability of a cell in response to a dynamical complex tumor microenvironment. In contrast to this idea, we postulate that cyclic attractors in certain cases could be a systemic mechanism to face the perturbations coming from the environment. To justify our conjecture, we present a dynamic analysis of a highly curated transcriptional regulatory network of macrophages constrained into a cancer microenvironment. We observed that when M1-associated transcription factors (STAT1 or NF-κB) are perturbed and the microenvironment balances to a hyper-inflammation condition, cycle attractors activate genes whose signals counteract this effect implicated in tissue damage. The same behavior happens when the M2-associated transcription factors are disturbed (STAT3 or STAT6); cycle attractors will prevent a hyper-regulation scenario implicated in providing a suitable environment for tumor growth. Therefore, here we propose that cyclic macrophage phenotypes can serve as a reservoir for balancing the phenotypes when a specific phenotype-based transcription factor is perturbed in the regulatory network of macrophages. We consider that cyclic attractors should not be simply ignored, but it is necessary to carefully evaluate their biological importance. In this work, we suggest one conjecture: the cyclic attractors can serve as a reservoir to balance the inflammatory/regulatory response of the network under external perturbations.

Facing the Increased Prevalence of Antibiotic-Resistant M. tuberculosis: Exploring the Feasibility of Realising Koch’s Aspiration of Immunotherapy of Tuberculosis

Koch attempted to treat tuberculosis in the late 1800s by administering an antigenic extract derived from the pathogen to patients. He hoped to bolster the patient’s protective immunity. The treatment had diverse results. In some, it improved the patient’s condition and in others led to a worsening state and even to death. Koch stopped giving his experimental treatment. I consider here three issues pertinent to realizing Koch’s vision. Rational immunotherapy requires a knowledge of what constitutes protective immunity; secondly, how on-going immune responses are regulated, so the patient’s immunity can be modulated to become optimally protective; thirdly, a simple methodology by which treatment might be realized. I deliberately cast my account in simple terms to transcend barriers due to specialization. The proposed immunotherapeutic treatment, if realizable, would significantly contribute to overcoming problems of treatment posed by antibiotic resistance of the pathogen.

Enhancing the efficacy of Hypericum perforatum in the treatment of an experimental model of multiple sclerosis using gold nanoparticles: an in vivo study

Objective

Hypericum perforatum is a herbal medicine used in traditional medicine for the treatment of depression due to its antidepressant and anti-inflammatory activities. Therefore, we evaluated the therapeutic efficacy of H. perforatum extract (HPE) in combination with gold nanoparticles (HPE-GNP) against experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis.

Materials and Methods

EAE was induced in C57BL/6 mice with subcutaneous injection of MOG35-55 emulsified in complete Freund's adjuvant, and intraperitoneal pertussis toxin. Mice were treated with drugs in free (HPE) and nano-form (HPE-GNP) preparations. Splenocytes were isolated from all mice and the level of inflammatory and anti-inflammatory cytokines were evaluated by ELISA. The expression of T cells' transcription factors was also assessed using Real-Time PCR.

Results

Clinical score was reduced after HPE-GNP treatment. This change was associated with a decrease in the incidence and infiltration of inflammatory cells into the central nervous system. Additionally, treatment with HPE-GNP decreased the level of pro-inflammatory cytokines (IFN-γ, IL-17A and IL-6) and increased anti-inflammatory cytokines (TGF-β, IL-10 and IL-4). The real-time analysis revealed a decrease in the level of T-bet and ROR-γt but an increase in FoxP3 and GATA3 expression.

Conclusion

The current study demonstrated that HPE-GNP could potentially reduce clinical and pathological complications of EAE, but laboratory data showed that HPE-GNP was significantly more effective than HPE in the treatment of EAE.

The role of cytokines in determining the Th1/Th2 phenotype of an immune response: Coherence of the T cell response and the Cytokine Implementation Hypothesis

The widely accepted Cytokine Milieu Hypothesis proposes that the cytokine milieu, in which antigen activates CD4 T cells, from a non‐T cell source, primarily determines the Th subset to which the ensuing effector Th cells belong. We focus on the generation of Th1 and Th2 cells. We briefly restate the grounds for the Threshold Hypothesis we favour for how the Th1/Th2 phenotype of a response is primarily determined: tentative and robust thresholds of antigen‐mediated CD4 T cell interactions lead to the generation of Th1 and Th2 cells. The component antigens of pathogens are present in different amounts. It is expected, within the context of the threshold mechanism that, although there is often an initial predominance of Th1 or Th2 cells, some Th cells of the opposing type are initially generated. An initially somewhat heterogeneous Th response is known to become with time more ‘coherent’ in its Th1/Th2 phenotype. I propose The Cytokine Implementation Hypothesis as a mechanism for how coherence is achieved. Most cytokines made by Th cells of one subset tend to facilitate the further generation of Th cells of this subset and/or inhibit the generation of Th cells of opposing subsets, accounting for how coherence may be achieved. Many observations on which The Cytokine Milieu Hypothesis is based are accounted for by this alternative hypothesis. We outline predictions of the new hypothesis and discuss the importance of coherence of immune responses for their efficacy in protecting against foreign invaders.

Annexin A1 as a Regulator of Immune Response in Cancer

Annexin A1 is a 37 kDa phospholipid-binding protein that is expressed in many tissues and cell types, including leukocytes, lymphocytes and epithelial cells. Although Annexin A1 has been extensively studied for its anti-inflammatory activity, it has been shown that, in the cancer context, its activity switches from anti-inflammatory to pro-inflammatory. Remarkably, Annexin A1 shows pro-invasive and pro-tumoral properties in several cancers either by eliciting autocrine signaling in cancer cells or by inducing a favorable tumor microenvironment. Indeed, the signaling of the N-terminal peptide of AnxA1 has been described to promote the switching of macrophages to the pro-tumoral M2 phenotype. Moreover, AnxA1 has been described to prevent the induction of antigen-specific cytotoxic T cell response and to play an essential role in the induction of regulatory T lymphocytes. In this way, Annexin A1 inhibits the anti-tumor immunity and supports the formation of an immunosuppressed tumor microenvironment that promotes tumor growth and metastasis. For these reasons, in this review we aim to describe the role of Annexin A1 in the establishment of the tumor microenvironment, focusing on the immunosuppressive and immunomodulatory activities of Annexin A1 and on its interaction with the epidermal growth factor receptor.

Booster immunization with a fractional dose of Prevnar 13 affects cell-mediated immune response but not humoral immunity in CD-1 mice

Achieving durable protective immunity following vaccination is dependent on many factors, including vaccine composition and antigen dose, and it has been investigated for various types of vaccines. Aim of the present study was to investigate the overall immune response elicited by two different booster doses in CD-1 mice, by exploiting the largely used 13-valent pneumococcal conjugate vaccine Prevnar 13® (PCV13). Immunization was performed by two primary doses of PCV13 two weeks apart, and a full or fractional (1/5) booster dose on week 10. Serotype-specific antibody titer, avidity, and opsonophagocytic activity were evaluated one week later, and compared to cell-mediated immunity (CMI) responses determined as the frequency of cytokines producing splenocytes by in vitro recall with the antigens (carrier protein and polysaccharides). Data showed that regardless of the booster dose, a comparable humoral response was produced, characterized by similar amounts of serotype-specific antibodies, with analog avidity and opsonophagocytic properties. On the other hand, when CMI was evaluated, the presence of CRM197-specific IL-5 and IL-2 producing cells was evident in splenocytes from mice immunized with the full dose, while in those immunized with the fractional booster dose, IFN-γ producing cells responsive to both protein and polysaccharide antigens were significantly increased, whereas the number of IL-5 and IL-2 positive cells remained unaffected. Overall the present findings show that PCV13 humoral response in mice is associated to a Th2 predominant response at the full booster dose, while the fractional one favors a mixed Th1/Th2 response, suggesting an important role of CMI besides measurement of functional protective antibodies, as an additional and important key information in vaccine development.

Phospholipase A2 Drives Tumorigenesis and Cancer Aggressiveness through Its Interaction with Annexin A1

Phospholipids are suggested to drive tumorigenesis through their essential role in inflammation. Phospholipase A₂ (PLA₂) is a phospholipid metabolizing enzyme that releases free fatty acids, mostly arachidonic acid, and lysophospholipids, which contribute to the development of the tumor microenvironment (TME), promoting immune evasion, angiogenesis, tumor growth, and invasiveness. The mechanisms mediated by PLA₂ are not fully understood, especially because an important inhibitory molecule, Annexin A1, is present in the TME but does not exert its action. Here, we will discuss how Annexin A1 in cancer does not inhibit PLA₂ leading to both pro-inflammatory and pro-tumoral signaling pathways. Moreover, Annexin A1 promotes the release of cancer-derived exosomes, which also lead to the enrichment of PLA₂ and COX-1 and COX-2 enzymes, contributing to TME formation. In this review, we aim to describe the role of PLA₂ in the establishment of TME, focusing on cancer-derived exosomes, and modulatory activities of Annexin A1. Unraveling how these proteins interact in the cancer context can reveal new strategies for the treatment of different tumors. We will also describe the possible strategies to inhibit PLA₂ and the approaches that could be used in order to resume the anti-PLA₂ function of Annexin A1.

Self-Adjuvant Effect by Manipulating the Bionano Interface of Liposome-Based Nanovaccines

Nanovaccines are of increasing scrutiny due to their plasticity in size, composition, and surface properties to enhance antigenicity. However, inevitable absorption of plasma proteins affects the in vivo fate of nanovaccines by reshaping biological identity. Herein IgM was validated as a self-adjuvant by regulating antigen-presenting cells recognition of liposome-based nanovaccines. ^DCDX-modified liposomes with loading of ovalbumin (^DCDX-sLip/OVA) heavily absorbed IgM via electrostatic interaction, demonstrating significant splenic B cells targeting. IgM absorbed on ^DCDX-sLip/OVA enhanced antigen uptake and presentation by both IgM-complement and IgM-FcμR pathways. ^DCDX-sLip/OVA induced a stronger IgG1 titer than ovalbumin-loaded plain liposomes (sLip/OVA) while maintaining a comparably high level of IgG2a titer with high biosafety, indicating that IgM absorption after ^DCDX modification could improve the antigenicity by enhancing the Th2-polarized immune response. The present work suggested manipulation of IgM absorption may provide a new impetus to improve in vivo performance of nanovaccines.

Differentiation and Regulation of TH Cells: A Balancing Act for Cancer Immunotherapy

Current success of immunotherapy in cancer has drawn attention to the subsets of T_H cells in the tumor which are critical for activation of anti-tumor response either directly by themselves or by stimulating cytotoxic T cell activity. However, presence of immunosuppressive pro-tumorigenic T_H subsets in the tumor milieu further contributes to the complexity of regulation of T_H cell-mediated immune response. In this review, we present an overview of the multifaceted positive and negative effects of T_H cells, with an emphasis on regulation of different T_H cell subtypes by various immune cells, and how a delicate balance of contradictory signals can influence overall success of cancer immunotherapy. We focus on the regulatory network that encompasses dendritic cell-induced activation of CD4⁺ T_H1 cells and subsequent priming of CD8⁺ cytotoxic T cells, along with intersecting anti-inflammatory and pro-tumorigenic T_H2 cell activity. We further discuss how other tumor infiltrating immune cells such as immunostimulatory T_H9 and T_fh cells, immunosuppressive T_reg cells, and the duality of T_H17 function contribute to tip the balance of anti- vs pro-tumorigenic T_H responses in the tumor. We highlight the developing knowledge of CD4⁺ T_H1 immune response against neoantigens/oncodrivers, impact of current immunotherapy strategies on CD4⁺ T_H1 immunity, and how opposing action of T_H cell subtypes can be explored further to amplify immunotherapy success in patients. Understanding the nuances of CD4⁺ T_H cells regulation and the molecular framework undergirding the balancing act between anti- vs pro-tumorigenic T_H subtypes is critical for rational designing of immunotherapies that can bypass therapeutic escape to maximize the potential of immunotherapy.

Pathogen Dose in Animal Models of Hemorrhagic Fever Virus Infections and the Potential Impact on Studies of the Immune Response

Viral hemorrhagic fever viruses come from a wide range of virus families and are a significant cause of morbidity and mortality worldwide each year. Animal models of infection with a number of these viruses have contributed to our knowledge of their pathogenesis and have been crucial for the development of therapeutics and vaccines that have been approved for human use. Most of these models use artificially high doses of virus, ensuring lethality in pre-clinical drug development studies. However, this can have a significant effect on the immune response generated. Here I discuss how the dose of antigen or pathogen is a critical determinant of immune responses and suggest that the current study of viruses in animal models should take this into account when developing and studying animal models of disease. This can have implications for determination of immune correlates of protection against disease as well as informing relevant vaccination and therapeutic strategies.

The Prognostic Value of Eosinophil Recovery in COVID-19: A Multicentre, Retrospective Cohort Study on Patients Hospitalised in Spanish Hospitals

OBJECTIVES

A decrease in blood cell counts, especially lymphocytes and eosinophils, has been described in patients with serious Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), but there is no knowledge of their potential role of the recovery in these patients' prognosis. This article aims to analyse the effect of blood cell depletion and blood cell recovery on mortality due to COVID-19.

DESIGN

This work was a retrospective, multicentre cohort study of 9644 hospitalised patients with confirmed COVID-19 from the Spanish Society of Internal Medicine's SEMI-COVID-19 Registry.

SETTING

This study examined patients hospitalised in 147 hospitals throughout Spain.

PARTICIPANTS

This work analysed 9644 patients (57.12% male) out of a cohort of 12,826 patients ≥18 years of age hospitalised with COVID-19 in Spain included in the SEMI-COVID-19 Registry as of 29 May 2020.

MAIN OUTCOME MEASURES

The main outcome measure of this work is the effect of blood cell depletion and blood cell recovery on mortality due to COVID-19. Univariate analysis was performed to determine possible predictors of death, and then multivariate analysis was carried out to control for potential confounders.

RESULTS

An increase in the eosinophil count on the seventh day of hospitalisation was associated with a better prognosis, including lower mortality rates (5.2% vs. 22.6% in non-recoverers, OR 0.234; 95% CI, 0.154 to 0.354) and lower complication rates, especially regarding the development of acute respiratory distress syndrome (8% vs. 20.1%, p = 0.000) and ICU admission (5.4% vs. 10.8%, p = 0.000). Lymphocyte recovery was found to have no effect on prognosis. Treatment with inhaled or systemic glucocorticoids was not found to be a confounding factor.

CONCLUSION

Eosinophil recovery in patients with COVID-19 who required hospitalisation had an independent prognostic value for all-cause mortality and a milder course.

Fermentation characteristics of novel Coriolus versicolor and Lentinus edodes kombucha beverages and immunomodulatory potential of their polysaccharide extracts

Medicinal mushrooms, Coriolus versicolor and Lentinus edodes are extremely attractive as nutraceuticals. Here we used fruiting bodies to prepare novel kombucha beverage. Microbiological, physicochemical and chemical properties were monitored for eleven days, while the immunological properties of kombucha polysaccharide extracts were determined in peripheral blood mononuclear cell (PBMC) cultures. FTIR analysis of polysaccharide extracts showed dominant presence of polysaccharides, in addition to phenols, lipids and proteins. C. versicolor kombucha extract displayed more complex polysaccharides, and a higher content of total polysaccharides, phenols and flavonoids compared to L. edodes kombucha extract. The extracts were not cytotoxic for PBMC in vitro up to 500 µg/ml, while immunomodulatory effects depended on their chemical compositions. The most prominent effect was on the reduction of Th2 cytokines and IL-10 in PBMC cultures. Based on these results, novel kombucha products could be recommended as functional beverages or nutraceuticals with potentially beneficial immunomodulatory effects in allergies.

Evaluation of Susceptibility and Innate Immune Response in C57BL/6 and BALB/c Mice During Candida albicans Endophthalmitis

Purpose

Candida remains the leading cause of fungal endophthalmitis. However, the pathobiology and innate immune responses in this disease are not well characterized. Here, we developed two murine models of candida endophthalmitis and evaluated their disease susceptibility and differential immune response.

Methods

Endophthalmitis was induced in C57BL/6 (B6) and BALB/c mice by intravitreal injection of Candida albicans (CA). Disease progression was monitored by slit-lamp examination and clinical scoring, followed by retinal function assessment using electroretinography (ERG). Enucleated eyes were used to estimate fungal burden and retinal tissue damage by hematoxylin and eosin and TUNEL staining. The level of inflammatory mediators were determined by quantitative Polymerase Chain Reaction (qPCR) and enzyme-linked immunosorbent assay, whereas neutrophil infiltration was assessed by flow cytometry and immunostaining.

Results

Intravitreal injection of CA at 6500 colony-forming units resulted in sustained (non-resolving) ocular inflammation in both B6 and BALB/c mice as evidenced by increased levels of inflammatory cytokines (tumor necrosis factor-α, interleukin-1β, and interleukin-6) and chemokine (CXCL2/MIP-2). In both mouse strains, fungal burden peaked at 24 to 48 hours post-infection (hpi) and decreased by 72 to 96 hpi. CA-infected eyes exhibited increased polymorphonuclear neutrophils (PMN) infiltration and retinal tissue damage. Overall retinal function declined rapidly, with a significant reduction in ERG response at 12 hpi and near-total loss by 24 hpi. Differential analyses revealed increased pathology in BALB/c versus B6 mice.

Conclusions

C. albicans was able to cause endophthalmitis in mice. Although BALB/c mice were found to be more susceptible to CA endophthalmitis, both BALB/c and B6 models could be used to study fungal endophthalmitis and test therapeutic modalities.

Can interruption/withdrawl of anti-retroviral therapy provide personalized immunotherapy against HIV-1?

We propose a treatment of HIV-1⁺ individuals designed to harness protective immunity, lead to viral containment, and so render the individual minimally infectious. A few HIV-infected individuals, 'elite controllers', generate a stable Th1, cytotoxic T lymphocyte response that contains the virus. Most infected individuals, in the absence of therapy, first generate a similarly protective response that evolves with time a Th2 component, associated with antibody production and loss of viral control. Cessation of anti-retroviral treatment after three years results in viral rebound in most, but about one in seven individuals contains the virus, so-called post-treatment controllers. We suggest an understanding, of how the Th1/Th2 phenotype of immune responses is controlled, can explain these different outcomes and leads us to propose a non-invasive, personalized strategy of immunotherapy. We propose that monitoring the relative prevalence of HIV-1 specific IgG₁ and IgG₂ antibodies can provide a biomarker for deciding when to interrupt/withdraw anti-retroviral therapy to optimally harness protective immunity.

Long noncoding RNA loss in immune suppression in cancer

Long noncoding RNAs (lncRNAs) have multiple functions in the regulation of cellular homeostasis. In recent years, numerous studies have shown that tumor-associated lncRNAs play key roles in promoting and maintaining tumor initiation and progression by shaping the tumor microenvironment through changing tumor cell intrinsic properties. Here, we focus on the roles of lncRNAs in cancer immunology. In the first part, we provide an overview of the roles played by lncRNAs and their deregulation in cancer at the cancer cell- and tumor microenvironment-associated immune cell levels. We go on to describe preclinical strategies for targeting lncRNAs, particularly highlighting the effects on tumor microenvironments. We then discuss the possibility of combining lncRNA targeting and tumor immune checkpoint inhibitor antibodies to treat cancer.