Journal of Immunotoxicology最新文献

Immunotherapeutics targeting immune checkpoint receptors or their ligands (i.e., immune checkpoint inhibitors), have been groundbreaking in the field of oncology, radically changing the approach to treatment and improving the clinical outcomes of an ever-expanding list of solid tumors and hematological malignancies. However, immune checkpoint inhibitors (ICI) are not devoid of side effects, collectively regarded as immune-related adverse events (irAE); they are not easily uncovered in preclinical immunotoxicological investigations and are often due to the very low expression of their targets in immunologically-unchallenged non-clinical species. We have characterized expression of a broad range of immune checkpoint receptors in peripheral blood mononuclear cell (PBMC) subpopulations from cynomolgus monkeys and healthy human volunteers, under resting and T-cell stimulatory conditions by multicolor flow cytometry to inform appropriate species selection for modeling potential irAE in immunotherapeutic preclinical research. Focusing on the response of the main lymphocyte populations to interleukin (IL)-2 alone, or in combination with anti-CD3 and anti-CD28 antibodies, checkpoints with shared similarities and key differences between the two species were identified. The results of this first study provide a database for the expression and response to stimulation for immune checkpoint receptors and can help guide future model selection in the design of preclinical studies involving immunotherapeutics directed against these targets.

Plantago asiatica L., a perennial herb in the family Plantaginaceae, has been shown to impart several pharmacologic activities, including anti-oxidative, anti-inflammatory, and diuretic effects. In the study here, the anti-gout(y) arthritis (GA) effects of a crude extract from P. asiatica L. (PAE) were investigated in a rat GA model. For this, PAE was prepared by ethanol extraction and analyzed for phytochemicals by RP-HPLC and Q-TOF-MS. Thereafter, potential therapeutic effects of the PAE were investigated in rats; Wistar rats (male, 8 wk-of-age) were randomly allocated into four groups (n = 9/group) and intra-articularly injected with 3 mg monosodium urate (MSU) in saline solution to establish a GA model. For the study, rats received oral dosings of 0.3 mg colchicine/kg or 1 g PAE/kg (w/w) before and after gout was established. At fixed times after the treatments, assessment of joint swelling ratios and pathological changes in the joints, as well as of select cytokine expression in the blood, was done. RP-HPLC results showed the PAE contained at least 8 'active' ingredients, with plantamajoside, verbascoside, and cymaroside being the most abundant. In comparison to in control rats, MSU induced joint space narrowing, ankle joint swelling, and increased levels of pro-inflammatory interleukin (IL)-1β, IL-17a, tumor necrosis factor (TNF)-α, and interferon (IFN)-γ, and reductions in anti-inflammatory IL-10 in the blood. PAE treatment significantly reversed patho- genic joint space narrowing and swelling, reversed the MSU-induced changes in inflammatory factors, and in general imparted effects very similar to those seen with colchicine (COL; known non-steroidal anti-inflammatory drug for clinical treatment of GA). Collectively, these findings provide experimental evidence supporting the potential applicability of PAE to treat gouty arthritis.

Efgartigimod is a human IgG₁ antibody F_c fragment that reduces IgG levels through neonatal F_c receptor blockade. This study evaluated whether efgartigimod affects the generation of T-cell-dependent antibodies and cellular immune responses to keyhole limpet hemocyanin (KLH) immunization in non-human primates. Cynomolgus monkeys received efgartigimod or vehicle control intravenously for 11 wk, followed by a recovery phase. KLH challenges occurred during both the dosing phase and the recovery phase. No statistically significant differences emerged in anti-KLH IgM levels between the efgartigimod and control groups. Likewise, comparable KLH-specific T cell responses were observed between groups. Anti-KLH IgG titers were lower in efgartigimod-treated animals compared with controls only after the first boost of KLH, coinciding with decreases in total IgG titers in efgartigimod-treated animals, and returned to baseline levels by the end of the recovery phase. Taken together, these results indicate that efgartigimod does not suppress T-cell-dependent antibody responses or antibody class-switching. The findings of this study are consistent with efgartigimod's pharmacological mechanism of action and suggest that efgartigimod does not impair the generation of effective immune responses.

Cell-mediated immune (CMI) responses to adeno-associated virus (AAV) can lead to tissue damage and loss of therapeutic transgene expression. Identifying robust biomarkers and mechanisms of CMI can aid clinical practice and advancement of AAV gene therapies. The present work evaluated peripheral blood mononuclear cells (PBMC) from non-human primates (NHP) before and after immunization with adenovirus 5 encoding AAV9 capsid antigen. PBMC were stimulated ex vivo with AAV9 capsid peptides to evaluate CMI responses by interferon (IFN)-γ ELISpot, intracellular cytokines/activation markers, secreted cytokines, and RNAseq. AAV peptide stimulation produced a robust IFNγ ELISpot 11 days after immunization and ≈ 4 years after cryopreservation. Flow cytometry revealed increased IFNγ, interleukin (IL)-2, or tumor necrosis factor (TNF)-positive T-cells. Increases in secreted CXCR3 ligands (IP-10, I-TAC) were detected. Robust changes and correlations to ELISpot responses were revealed by RNAseq, including IFNγ, IP-10, and I-TAC, many downstream transcripts, and several IFN-independent pathways. These data from AAV-immunized NHP identify biomarkers that could serve as robust and sensitive supplements/alternatives to ELISpot for early detection of CMI responses. Assessment of these biomarkers in non-clinical and clinical studies is a critical next step to determine the translation of this work to administration of a therapeutic AAV vector.

The demand for botanicals and natural substances in consumer products has increased in recent years. These substances usually contain proteins and these, in turn, can pose a risk for immunoglobulin E (IgE)-mediated sensitization and allergy. However, no method has yet been accepted or validated for assessment of potential allergenic hazards in such materials. In the studies here, a dual proteomic-bioinformatic approach is proposed to evaluate holistically allergenic hazards in complex mixtures of plants, insects, or animal proteins. Twelve commercial preparations of source materials (plant products, dust mite extract, and preparations of animal dander) known to contain allergenic proteins were analyzed by label-free proteomic analyses to identify and semi-quantify proteins. These were then evaluated by bioinformatics using AllerCatPro 2.0 (https://allercatpro.bii.a-star.edu.sg/) to predict no, weak, or strong evidence for allergenicity and similarity to source-specific allergens. In total, 4,586 protein sequences were identified in the 12 source materials combined. Of these, 1,665 sequences were predicted with weak or strong evidence for allergenic potential. This first-tier approach provided top-level information about the occurrence and abundance of proteins and potential allergens. With regards to source-specific allergens, 129 allergens were identified. The sum of the relative abundance of these allergens ranged from 0.8% (lamb's quarters) to 63% (olive pollen). It is proposed here that this dual proteomic-bioinformatic approach has the potential to provide detailed information on the presence and relative abundance of allergens, and can play an important role in identifying potential allergenic hazards in complex protein mixtures for the purposes of safety assessments.

Efficacious therapeutic options capable of resolving inflammatory lung disease associated with environmental and occupational exposures are lacking. This study sought to determine the preclinical therapeutic potential of lung-delivered recombinant interleukin (IL)-10 therapy following acute organic dust exposure in mice. Here, C57BL/6J mice were intratracheally instilled with swine confinement organic dust extract (ODE) (12.5%, 25%, 50% concentrations) with IL-10 (1 μg) treatment or vehicle control intratracheally-administered three times: 5 hr post-exposure and then daily for 2 days. The results showed that IL-10 treatment reduced ODE (25%)-induced weight loss by 66% and 46% at Day 1 and Day 2 post-exposure, respectively. IL-10 treatment reduced ODE (25%, 50%)-induced lung levels of TNFα (-76%, -83% [reduction], respectively), neutrophil chemoattractant CXCL1 (-51%, -60%), and lavage fluid IL-6 (-84%, -89%). IL-10 treatment reduced ODE (25%, 50%)-induced lung neutrophils (-49%, -70%) and recruited CD11c^intCD11b⁺ monocyte-macrophages (-49%, -70%). IL-10 therapy reduced ODE-associated expression of antigen presentation (MHC Class II, CD80, CD86) and inflammatory (Ly6C) markers and increased anti-inflammatory CD206 expression on CD11c^intCD11b⁺ cells. ODE (12.5%, 25%)-induced lung pathology was also reduced with IL-10 therapy. In conclusion, the studies here showed that short-term, lung-delivered IL-10 treatment induced a beneficial response in reducing inflammatory consequences (that were also associated with striking reduction in recruited monocyte-macrophages) following acute complex organic dust exposure.

The prevalence of pre-diabetes is increasing in rapidly urbanizing cities, especially in individuals aged 25 - 45 years old. Studies also indicate that this condition is associated with aberrant immune responses that are also influenced by environmental factors. This study sought to investigate changes in the concentration of immune cells and select inflammatory markers in patients with pre-diabetes in Durban, South Africa. Blood samples collected from King Edward Hospital, after obtaining ethics approval, were divided into non-diabetic (ND), pre-diabetic (PD) and type 2 diabetic (T2D) using ADA criteria. In each sample, the concentration of immune cells and select inflammatory markers were determined. The results showed a significant increase in eosinophil and basophil levels in the PD group as compared to the ND group. Compared to ND, the PD and T2D groups had significant increases in serum TNFα, CD40L and fibrinogen concentrations. Additionally, there were decreases in serum CRP, IL-6, and P-selectin in the PD group while these markers increased in the T2D group. These findings were indicative of immune activation and highlight the impact of pre-diabetes in this population. More studies are recommended with a higher number of samples that are stratified by gender and represent the gender ratio in the city.

The fundamental goal of this study was to determine the potential utility of a novel humanized Toll-like receptor-4 (hTLR-4) mouse model for future in vivo studies of nickel allergy. First, mice of both sexes and hTLR-4 expression profiles were incorporated into a Local Lymph Node Assay (LLNA) to assess skin sensitization. Next, a set of hTLR-4 hTLR-4-positive mice (female and male groups) was similarly exposed to vehicle control (VC) or 10% NiSO₄ on Days 1, 2, and 3. Mice were euthanized on Day 10, lymph node (LN) cellularity was assessed, LN and spleen cells were phenotyped, and serum was collected to quantify circulating cytokine and IgE levels. In the LLNA, hTLR-4-positive mice of both sexes exhibited enhanced responsivity to nickel. NiSO₄ (10%) had a stimulation index (SI) of 3.7 (females) and 3.8 (males) in hTLR-4-positive animals, and an SI of 0.5 (females) and 0.8 (males) in hTLR-4 hTLR-4-negative mice. In the 10d study, hTLR-4-positive mice exposed to 10% NiSO₄ exhibited increased LN cellularity (6.0× increase in females, 3.2× in males) and significantly higher concentrations of circulating IgE (4.1× increase in females, 3.4× in males). Significant increases in serum interferon (IFN)-γ, interleukin (IL)-4, and IL-5 levels were seen in female mice, while altered concentrations of IL-4 and IL-10 were detected in male mice. The results of this study ultimately demonstrate that murine expression of hTLR-4 confers enhanced susceptibility to dermal sensitization by nickel, and consequently, the hTLR-4 mouse model represents a viable approach for future studies of nickel allergy in vivo.

Molecular mimicry has been proposed to be a possible mechanism of induction of autoimmunity. In some cases, it is believed that such events could lead to a disease such as Type 1 diabetes (T1D). One of the primary MHC-I epitopes in the non-obese diabetic (NOD) mouse model of T1D has been identified as a peptide from the islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP) protein. In humans, the most common MHC-I model allele is HLA-A02; based on this, the study here identified a potential HLA-A0201-restricted human IGRP epitope as YLKTNLFLFL and also found a homologous A0201-restricted peptide in an Enterococcal protein. Using cells obtained from healthy human donors, it was seen that after a 2-week incubation with the synthetic bacterial protein, healthy A0201⁺ donor CD8⁺ cells displayed increased staining for human IGRP-peptide-dextramer. On the other hand, in control cultures, no significant levels of dextramer-staining CD8⁺ T-cells were detectable. From these outcomes, it is possible to conclude that certain bacterial proteins may initiate CD8⁺ T-cell-mediated immune reaction toward homologous human antigens.

Cetylpyridinium chloride (CPC) is a quaternary ammonium antimicrobial used in numerous personal care products, human food, cosmetic products, and cleaning solutions. Yet, there is minimal published data on CPC effects on eukaryotes, immune signaling, and human health. Previously, it was shown that low-micromolar CPC inhibits rat mast cell function by inhibiting antigen (Ag)-stimulated Ca²⁺ mobilization, microtubule polymerization, and degranulation. In the current study, these findings are extended to human mast cells (LAD2); this paper presents data indicating that a mechanism of action for CPC might center on its positively-charged quaternary nitrogen in its pyridinium headgroup. The inhibitory effect of CPC was independent of signaling platform receptor architecture. Tyrosine phosphorylation events are a trigger of Ca²⁺ mobilization necessary for degranulation. CPC inhibits global tyrosine phosphorylation in Ag-stimulated mast cells. Specifically, CPC inhibits tyrosine phosphorylation of specific key players Syk kinase and LAT, a substrate of Syk. In contrast, CPC did not affect Lyn kinase phosphorylation. Thus, a root mechanism for CPC effect might be electrostatic disruption of particular tyrosine phosphorylation events essential for signaling. This work presented here outlines biochemical mechanisms underlying the effects of CPC on immune signaling.