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PubMedDate not supplied

In vitro immune modulation by thymosin alpha 1 in patients with head and neck squamous cell carcinoma.

To determine if patients with head and neck squamous cell carcinoma represent an appropriate population for immune reconstitution with thymosin alpha 1, leukocyte migration inhibition (LMI) in response to phytohemagglutinin was measured in 24 previously untreated patients with head and neck cancer, and the in vitro effects of thymosin alpha 1 on migration inhibition were assessed. Compared to normal subjects, LMI was impaired in the head and neck cancer patients. Thymosin alpha 1, in vitro, was associated with improvement in LMI in the cancer patients. Improvements in migration response with thymosin alpha 1 appeared to be independent of levels of various T-lymphocyte subpopulations. However, patients with a normal LMI response had lower suppressor/cytotoxic cell levels than normal subjects or patients with impaired LMI. The findings confirm prior reports of the effects of thymic hormones on lymphokine production in vitro and provide rationale for further clinical studies of thymosin alpha 1 in patients with head and neck squamous cell carcinoma.

Aged↗
PubMed1997

Activation or frustration of anti-tumor responses by T-cell-based immune modulation.

Many types of tumors (e.g. virus-induced tumors, melanomas, tumors over-expressing certain oncogenes) often express antigens that can induce T-cell-mediated tumor-specific immune responses. Nonetheless, many such tumors manage to circumvent the induction of an effective anti-tumor T-cell response, as is apparent from the many tumor-bearing patients. Therefore, optimally designed vaccination protocols may evoke a more powerful and competent T-cell-mediated anti-tumor response, allowing the host to effectively deal with at least some cancers. These vaccination approaches might include immunization with whole (tumor) cell-based vaccines, entire tumor antigens or selected T-cell epitopes derived from tumor antigens. This survey is an update of several anti-tumor vaccination approaches employed, and on novel possibilities to target the anti-tumor immune response to preselected tumor-derived T-cell epitopes.

Adenoviridae↗
PubMed2006

Immunologic control of tumors by in vivo Fc gamma receptor-targeted antigen loading in conjunction with double-stranded RNA-mediated immune modulation.

Despite the expression of non-self or neo-epitopes, many tumors such as lymphoid malignancies or cancers induced by oncogenic viruses are able to gradually overcome the immune defense mechanisms and spread. Using a preclinical model of hematological malignancy, we show that Ig-associated idiotypic determinants are recognized by the immune system in a fashion that results in immune deviation, allowing tumor progression and establishment of metastases. Using gene-targeted mice, we show that anti-idiotypic MHC class I-restricted immunity is promoted by ITAM motif (ITAM+) FcgammaR, but kept in check by ITIM motif (ITIM+) FcgammaRIIB-mediated mechanisms. In addition to interfering with the functionality of ITIM+ FcgammaR, effective anti-idiotypic and antitumoral immunity can be achieved by FcgammaR-targeted delivery of epitope in conjunction with administration of stimulatory motifs such as dsRNA, correcting the ineffective response to idiotypic epitopes. The immune process initiated by FcgammaR-mediated targeting of epitope together with dsRNA, resulted in control of tumor growth, establishment of immune memory and protection against tumors bearing antigenic variants. In summary, targeted delivery of MHC class I-restricted epitopes via ITAM+ FcgammaR, in conjunction with use of TLR-binding immune stimulatory motifs such as dsRNA, overcomes suboptimal responses to idiotypic determinants and may constitute a novel approach for the treatment of a broad range of malignancies. Finally, the results shed light on the mechanisms regulating the idiotypic network and managing the diversity associated with immune receptors.

Animals↗
PubMed2026

Streptococcus pneumoniae adaptation to nutrient deprivation and immune modulation drives upper respiratory tract colonization.

Streptococcus pneumoniae is a successful colonizer of the human upper respiratory tract; however, the mechanisms that enable its persistence in this nutrient-limited environment, with numerous immune mechanisms in place, remain enigmatic. Here, we examined how pneumococci adapt to upper respiratory tract conditions and how this affects host interactions. We measured intranasal metal ion and monosaccharide concentrations to create an in vivo-mimicking medium for studying pneumococcal adaptation. Growth in this medium was reduced compared to glucose-rich chemically defined media (CDM). Proteome analysis revealed a shift to galactose as the major carbohydrate source, and decreased levels of fatty acid biosynthesis proteins and pneumolysin, compared to other CDMs. Glycerophosphocholine accumulated extracellularly leading to decreased C-reactive protein and Immunoglobulin M binding to pneumococci. Pneumococci grown in in vivo-mimicking medium, compared to glucose-rich media, were more capable colonizers of primary epithelium and induced less epithelial cytokine release. Together, this shows how pneumococci adapt to the nutrient-limited respiratory environment, modulate epithelial cells, and evade humoral responses to facilitate persistent colonization.

Streptococcus pneumoniae↗
PubMed1996

Update on the mechanisms of immune suppression of injury and immune modulation.

Major trauma results in massive impairment of immunologic reactivity, the clinical consequence of which consists in the high susceptibility of the traumatized individual toward serious infection. Whereas parts of the immune system are stimulated within a systemic, nondiscriminant, excessive whole-body inflammation, other functions within the complex of cell-mediated immunity (CMI) are dramatically paralyzed. Immune abnormalities in the aftermath of trauma occur in a sequence of states of cellular activation and within a complex order of events that is not yet well understood. Traumatic stress is causing disintegration of the intact monocyte (Mphi)-T cell interaction, which is associated with profound changes in Mphi forward-regulatory capacities and substantial depression of T cell function. Extensive tissue destruction results in the generation of numerous stimuli, such as phagocytosis, immune complexes, complement split products, and endo- and exotoxins, all of which contribute to excessive Mphi activation. Mphi then rapidly produce and release prostaglandin E2 (PGE2), a powerful endogenous immune suppressant. PGE2 is an inhibitor of T cell mitogenesis, interleukin 2 (IL-2) production, and IL-2 receptor expression; and it has a massive impact on the quality of B cell antibody synthesis. Most importantly, PGE2 represents an important cofactor for the induction of T-helper lymphocyte (TH) activity toward the TH2 direction. TH2 cells are associated with the synthesis of immunosuppressive cytokines, such as IL-4 and IL-10. Although immunosuppressive substrates are inhibitory for TH1 cells-the functional carriers of CMI-they support TH2 activity, which predisposes the host to develop infection. The endogenous ability of the organism to survive overwhelming trauma is insufficient and requires major exogenous support. Immune modulatory interventions, depending on the immune abnormalities seen in the traumatized host, should be started as early as possible after trauma in a preventive fashion to protect against organ tissue destruction. Ideally, it should protect all cellular host defense compartments from hyperactivation as well as from exhaustion. We do believe that only a combination of drugs can effectively control the posttraumatic dyshomeostasis of the various cell systems.

Adjuvants, Immunologic↗
PubMed1988

Immune modulation by Coxiella burnetii: characterization of a phase I immunosuppressive complex differentially expressed among strains.

Coxiella burnetii, the etiological agent of Q fever, possesses immunomodulatory activity which positively and negatively regulates host immune responses. We wish to determine the Coxiella strain differences and the chemical nature of cellular components suppressing lymphocyte responsiveness. The bacterial components responsible for the immunomodulatory activity are associated with phase I cells. In its natural state, the phase I cell-associated, immunosuppressive complex (ISC) was resistant to chemical and enzymatic treatment. The ISC was inactivated and rendered accessible by chloroform-methanol (CM) (4:1) extraction of phase I cells which produced a CM residue (CMRI) and CM extract (CME). The suppressive components in either CMRI or CME did not induce ISC activity in the host when injected separately. Reconstitution of the CMRI with CME prior to injection produced the same pathological reactions characteristic of phase I cells. The CMRI suppressive component was sensitive to alkali, acid, periodate, lysozyme, and neuraminidase, but resistant to lipase and protease. An active component of CMRI was attached to the cell matrix by disulphide bonds. The amphipathic, lipophilic, CME suppressive component was ubiquitously distributed in procaryotes and eukaryotes because ISC activity of CMRI was regained after association with reagent-grade lipids and different CMEs. The ISC was expressed by phase I strains with smooth lipopolysaccharide (LPS) but not by phase II strains with rough LPS. Phase I heart valve strains carrying significant amounts of rough LPS did not express all of the biological properties of the ISC. The LPS molecule induced immune enhancement without immunosuppression. Thus, expression of the ISC showed strain variation and may be under genetic control. The complete details of the chemical composition and active components of the ISC should prove useful for biological-response-modification studies.

Adsorption↗
PubMed2005

Carvedilol improves left ventricular function in murine coxsackievirus-induced acute myocarditis association with reduced myocardial interleukin-1beta and MMP-8 expression and a modulated immune response.

BACKGROUND: Proinflammatory cytokines induce the expression of matrix metalloproteinases that play a crucial role in myocardial remodeling. Beta-adrenergic receptor stimulation influences the production of cytokines heralding the possibility of modulating cytokine production by beta-adrenergic blockers. METHODS AND RESULTS: In a coxsackievirus B3 murine myocarditis model (BALB/c), effects of carvedilol and metoprolol on myocardial cytokine expression, inflammatory cell infiltration and MMP/TIMP profiles were investigated. In carvedilol-treated mice, a significant improvement in left ventricular function was documented 10 days post infection. In infected mice (n=10), IL-1beta, TNF-alpha, TGF-beta(1) and IL-10 myocardial mRNA abundance were increased significantly (240%, 200%, 161%, and 230%) compared to controls (n=10), while IL-15 mRNA was markedly reduced (70%). Infected mice showed significantly increased infiltrations with CD3-, CD4- and CD8-T-lymphocytes (730%, 1110%, 380%). In the infected mice, myocardial MMP/TIMP profiles presented a significant upregulation of membrane type-1 MMP, MMP-9, MMP-8 and MMP-3 (150%, 160%, 340%, and 270%) and a significant decrease in TIMP-4 levels (75%). Carvedilol attenuated over-expression of myocardial TGF-beta(1), IL-1beta and MMP-8 mRNA expression significantly and induced a relevant IL-10 mRNA expression in the infected mice (n=10). By an unchanged infiltration with CD3-T-lymphocytes, carvedilol showed a representative reduction in CD4-T-lymphocytes. CONCLUSION: Carvedilol treatment in experimental myocarditis leads to reduced expression of proinflammatory cytokines and MMPs, which contributes to reduced matrix degradation and ultimately to improved structural integrity of the heart. Besides the antiadrenergic potential, carvedilol is beneficial due to a wide range of biological activities (antiinflammatory, antifibrotic, antioxidative and immunomodulatory).

Adrenergic beta-Antagonists↗
PubMed2001

Immunopathogenesis and immune modulation of Venezuelan equine encephalitis virus-induced disease in the mouse.

The course of Venezuelan equine encephalitis (VEE) disease in immunodeficient and immunologically normal mice was compared to define the role of the immune system in this disease process. Immunocompetent mice infected with VEE exhibited a biphasic illness characterized by an early self-limiting lymphoid phase and a fatal CNS phase. The lymphoid phase of the illness was characterized by extensive viral replication within spleen, thymus, Peyer's patches, and lymph nodes, was accompanied by a high-titered serum viremia, and resolved with the production of VEE-specific IgM class antibody at 72 h postinfection (p.i.). Immunocompetent animals survived an average of 6.8 +/- 1.2 days before succumbing to fulminant encephalitis. In contrast, SCID mice infected with VEE showed a persistent replication of virus throughout all organs tested beginning at 24 h p.i. VEE-infected SCID mice exhibited a severe spongiform encephalopathy with 100% mortality and an average survival time of 8.9 +/- 0.9 days. These studies indicated that the characteristic organ tropism of VEE in the mouse is due in large part to an early anti-viral state, the establishment of which is dependent upon the presence of an intact immune system. Finally, the CNS pathology in a VEE-infected mouse had a significant immunologic component. However, in contrast to other neurovirulent alphaviruses, VEE was directly cytopathic for the cells of the CNS, even in the absence of an immune response.

Animals↗
PubMed2002

A Tat subunit vaccine confers protective immunity against the immune-modulating activity of the human immunodeficiency virus type-1 Tat protein in mice.

The rational design of new therapies against HIV-1 necessitates an improved understanding of the mechanisms underlying the production of ineffective immune responses to HIV-1 in most infected individuals. This report shows that the CD8(+) T cell responses to gp120 were greatly diminished in mice vaccinated with a bicistronic gp120-Tat DNA vaccine, compared with those induced by a DNA vaccine encoding gp120 alone. The CD8(+) T cell responses induced by the latter included strong gp120-specific IFN-gamma secretion and protective antiviral immunity against challenge by a vaccinia-env pseudotype. The degree to which Tat influenced CD8(+) T cell responses depended on the bioactivity of Tat. Thus, a bicistronic DNA vaccine that expresses gp120 and a truncated Tat defective for LTR activation elicited strong IFN-gamma -secreting CD8(+) T cell responses to gp120 but conferred only marginal protection against the vaccinia-env challenge. The effect of Tat was completely blocked, however, by immunization with inactivated Tat protein before vaccination with the bicistronic gp120-Tat DNA vaccine.

AIDS Vaccines↗
PubMedDate not supplied

Immune modulator studies in primates: the utility of flow cytometry and immunohistochemistry in the identification and characterization of immunotoxicity.

Exposure to natural environmental products, biopharmaceuticals, or investigational adjuvants has the potential to negatively impact the immune system, resulting in either up- or downregulation of immune function (immunomodulation). Many current protocols for primate toxicologic testing call for the evaluation of changes in immune cell number (peripheral blood or tissue), alterations in the weights of immune system organs (lymph nodes, spleen, thymus), and/or increases in the overall incidence of infections or neoplasms; these data are relied upon to suggest altered immune function. However, these are informative only when clear differences in frequency and/or severity of effects can be distinguished across control and dosed groups. In the absence of such distinct morphologic or clinical pathologic changes, the identification of potential immunomodulatory effects can present a much greater challenge. Additional evaluations may be needed to detect altered immune system integrity; these are based on in vivo assessments in primates of cellular or humoral responsiveness. Immunomodulatory effects can be characterized by in vitro or in vivo immune function tests: these tests require prestudy planning to integrate assessments into ongoing toxicology programs. These methods also involve specialized training and equipment, particularly if the intent is to evaluate parameters in a GLP laboratory setting. In primate toxicology, the added costs required to perform a complete functional analysis of the immune system can be substantial, but may be warranted depending on the clinical development plans. Two analytical methods that are easily incorporated into the standard toxicology profile in primates are flow cytometry and immunohistochemistry. Flow cytometry (FC) is used to assess changes in the relative distribution of immune cell marker expression, and where marker expression is known to fluctuate with the state of cell activation, can also provide information on functional attributes of immune cells. Immunohistochemistry (IHC) provides a means to evaluate similar characteristics of immune cells within tissue sections. Used together, FC and IHC can aid in the identification of changes in immune system that may not be apparent by traditional testing procedures (such as H&E staining), thus aiding in the characterization of immune system alterations. This presentation focused on the utility of flow cytometry and immunohistochemistry in a standard primate toxicology evaluation, with representative examples showing the benefits of these technologies in the diagnosis of potential immunomodulatory effects.

Adjuvants, Immunologic↗
PubMed1978

Effect of thymosin and irradiation on immune modulation in head and neck and esophageal cancer patients.

Fifty-five patients with squamous cell carcinoma of the head and neck and esophagus were evaluated prior to irradiation and thymosin fraction 5 therapy. Immunity prior to treatment, as measured by total lymphocyte count, E and EAC rosettes, lymphocyte stimulation with phytohemagglutinin (PHA) and in mixed leukocyte culture (MLC) with allogeneic cells, delayed hypersensitivity skin tests, and quantitative serum immunoglobulins, was comparable and normal in the 40 control patients and in the 15 thymosin-treated patients. After irradiation, significant depression (P less than 0.01) was demonstrated in cellular immunity in both groups of patients with decreased T- and B-cell numbers and depressed phytohemagglutinin and MLC stimulation. Six months after irradiation, our preliminary results suggest that the thymosin-treated patients may be reversing their immunosuppression by a return of MLC function and positivity of delayed hypersensitivity skin tests. The ultimate effect of thymosin on disease control and survival remains uncertain.

Carcinoma, Squamous Cell↗
PubMed2025

Oncogenic EME1 promotes tumor progression and immune modulation in human cancers with therapeutic targeting potential.

BACKGROUND: EME1, a critical DNA repair endonuclease, has emerged as a potential oncogene implicated in genome instability and cancer progression. However, its pan-cancer roles, prognostic significance, immune interactions, and therapeutic targeting remain underexplored. METHODS: We conducted a comprehensive pan-cancer analysis integrating multi-omics data from public databases, including TIMER2.0, GEPIA2, TISIDB, and cBioPortal, to evaluate EME1 expression, genetic alterations, and their association with clinical outcomes, immune infiltration, and molecular pathways. Virtual screening of 3180 FDA-approved drugs and molecular dynamics (MD) simulations were employed to identify and validate potential EME1 inhibitors. RESULTS: EME1 was significantly overexpressed in various human cancers and positively associated with advanced tumor grade and stage. High EME1 expression and mutations were linked to poor overall and disease-free survival. Immunogenomic profiling revealed strong positive correlations between EME1 and myeloid-derived suppressor cells (MDSCs), alongside a negative association with endothelial cell function, suggesting immunosuppressive roles. Machine learning models based on EME1-associated genes demonstrated high predictive accuracy for liver hepatocellular carcinoma (AUC > 0.90). Virtual screening identified eight promising drug candidates, including Everolimus and Dioscin, with strong binding affinities. MD simulations confirmed the stability of these interactions, particularly for Dioscin. CONCLUSION: This study reveals the multifaceted oncogenic roles of EME1 in tumor progression, immune evasion, and prognosis. It proposes EME1 as a promising biomarker and therapeutic target across multiple cancer types. The identified drug candidates warrant further in vitro and in vivo validation for potential repurposing in EME1-targeted cancer therapy.

EME1↗