Staphylococcal enterotoxin B-derived haptens promote sensitization

The effects of vitamin D on different types of cells

Vitamin D is neccessary for regulation of calcium and phosphorus metabolism in bones, affects imunity, the cardiovascular system, muscles, skin, epithelium, extracellular matrix, the central nervous system, and plays arole in prevention of aging-associated diseases. Vitamin D receptor is expressed in almost all types of cells and its activation leads to modulation of different signaling pathways. In this review, we have analysed the current knowledge of 1,25-dihydroxyvitamin D3 or 25-hydroxyvitamin D3 effects on metabolism of cells important for the function of the cardiovascular system (endothelial cells, vascular smooth muscle cells, cardiac cells and pericytes), tissue healing (fibroblasts), epithelium (various types of epithelial cells) and the central nervous system (neurons, astrocytes and microglia). The goal of this review was to compare the effects of vitamin D on the above mentioned cells in in vitro conditions and to summarize what is known in this field of research.

Intrapleural Perfusion With Staphylococcal Enterotoxin C for Malignant Pleural Effusion: A Clustered Systematic Review and Meta-Analysis

Introduction

The staphylococcal enterotoxin C (SEC), a commercially available bio-product from Staphylococcus aureus (S. aureus), has been widely used to control MPE.

Objectives

We designed and performed a new systematic review (SR) and meta-analysis to clarify the perfusion protocols with SEC, determine their clinical effectiveness and safety, and reveal the indication and optimum usage for achieving the desired responses.

Methodology

All randomized controlled trials (RCTs) about SEC for MPE were collected from electronic databases (from inception until July 2021), and clustered into multiple logical topics. After evaluating their methodological quality, we pooled the data from each topic using the meta-analysis or descriptive analysis, and summarized the evidence quality using the grading of recommendation assessment, development, and evaluation (GRADE) approach.

Results

All 114 studies were clustered into SEC perfusion alone or plus chemical agents. The SEC alone showed a better complete response (CR), a lower pleurodesis failure, and adverse drug reactions (ADRs), and a higher fever than cisplatin (DDP) alone. The SEC and chemical agents developed 10 perfusion protocols. Among them, only SEC and DDP perfusion showed a better CR, a lower failure, disease progression and ADRs, and a higher fever than DDP alone. The SEC (100–200 ng per time, one time a week for one to four times) with DDP (30–40 mg, or 50–60 mg each time) significantly improved clinical responses for patients with moderate to large volume, Karnofsky performance status (KPS) scores ≥40, ≥50, or ≥60, and anticipated survival time (AST) ≥2 or 3 months. Most results were moderate to low quality.

Conclusion

Current pieces of evidence indicate that super-antigen SEC is a pleurodesis agent, which provides an attractive alternative to existing palliative modalities for patients with MPE. Among 10 protocols, the SEC and DDP perfusion is a most commonly used, which shows a significant improvement in clinical responses with low ADRs. These findings also provide a possible indication and optimal usage for SEC and DDP perfusion.

Forkhead box protein-3 (Foxp3)-producing dendritic cells suppress allergic response

BACKGROUND

The generation of the tolerogenic dendritic cells (DC) is not fully understood yet. Forkhead box protein-3 (Foxp3) is an important molecule in the immune tolerance. This study tests a hypothesis that DCs express Foxp3, which can be upregulated by Staphylococcal enterotoxin B (SEB).

METHODS

The expression of Foxp3 by DCs was evaluated by real-time RT-PCR, Western blotting, flow cytometry, and chromatin immunoprecipitation assay.

RESULTS

We observed that mice treated with SEB at 0.25-0.5 μg/mouse showed high frequencies of transforming growth factor (TGF)-β-producing CD4⁺ T cells and TGF-β-producing DCs in the intestine, while the IL-4⁺ CD4⁺ T cells and TIM4⁺ DCs were dominated in the intestine in mice treated with SEB at 1-10 μg/mouse. Treating DCs with SEB in the culture induced high levels of Foxp3 at the TGF-β promoter locus. The function of Foxp3 was blocked by STAT6 (signal transducer and activator transcription-6); the latter was induced by exposing DCs to SEB in the culture at doses of 100-400 ng/ml. Treating allergic mice with specific immunotherapy (SIT) together with SEB significantly promoted the therapeutic effects on the allergic responses than treating with SIT alone.

CONCLUSION

Dendritic cells have the capacity to express Foxp3, which can be upregulated by exposure to SEB.

Inhibition of squamous cancer growth in a mouse model by Staphylococcal enterotoxin B-triggered Th9 cell expansion

Currently, therapy for squamous cancer (SqC) is unsatisfactory. Staphylococcal enterotoxin B (SEB) has strong immune regulatory activity. This study tests the hypothesis that SEB enforces the effect of immunotherapy on SqC growth in a mouse model. C3H/HeN mice and the SqC cell line squamous cell carcinoma VII were used to create an SqC mouse model. Immune cell assessment was performed by flow cytometry. Real-time RT-PCR and western blotting were used to evaluate target molecule expression. An apoptosis assay was used to assess the suppressive effect of T helper-9 (Th9) cells on the SqC cells. The results showed that immunotherapy consisting of SEB plus SqC antigen significantly inhibited SqC growth in the mice. The frequency of Th9 cells was markedly increased in the SqC tissue and mouse spleens after treatment. SEB markedly increased the levels of signal transducer and activator of transcription 5 phosphorylation and the expression of histone deacetylase-1 (HDAC1) and PU.1 (the transcription factor of the interleukin 9 (IL-9) gene) in CD4⁺ T cells. Exposure to SqC-specific Th9 cells markedly induced SqC cell apoptosis both in vitro and in vivo. In conclusion, the administration of SEB induces Th9 cells in SqC-bearing mice, and theseTh9 cells inhibit SqC growth.

Cardiac endothelial cell-derived exosomes induce specific regulatory B cells

The mechanism of immune tolerance is to be further understood. The present study aims to investigate the role of the Cardiac endothelial cell (CEC)-derived exosomes in the induction of regulatory B cells. In this study, CECs were isolated from the mouse heart. Exosomes were purified from the culture supernatant of the primary endothelial cells. The suppressor functions of the regulatory B cells were determined by flow cytometry. The results showed that the CEC-derived exosomes carried integrin αvβ6. Exposure to lipopolysaccharide (LPS) induced B cells to express the latent transforming growth factor (TGF)-β, the latter was converted to the active form, TGF-β, by the exosome-derived αvβ6. The B cells released TGF-β in response to re-exposure to the exosomes in the culture, which suppressed the effector T cell proliferation. We conclude that CEC-derived exosomes have the capacity to induce B cells with immune suppressor functions.

Staphylococcal enterotoxin B suppresses Alix and compromises intestinal epithelial barrier functions

Background

The epithelial barrier dysfunction plays a critical role in the pathogenesis of a broad array of immune diseases. Alix protein is involved in the endolysosome system. This study aims to elucidate the role of Alix in the maintenance of epithelial barrier function.

Results

The results showed that Alix was detected in T84 cells at both mRNA and protein levels. Exposure to Staphylococcal enterotoxin B (SEB) markedly suppressed the expression of Alix in T84 cells, which could be blocked by knocking down the Toll like receptor 2. The exposure to SEB did not affect the TER, but markedly increased the permeability of T84 monolayers to OVA; the OVA passing through T84 monolayers still preserved the antigenicity manifesting inducing antigen specific T cells proliferation.

Conclusions

Alix protein plays a critical role in the maintenance of the barrier function of T84 monolayers.