Staphylococcal enterotoxin B stimulates expansion of autoreactive T cells that induce apoptosis in intestinal epithelial cells: regulation of autoreactive responses by IL-10

Potential application mechanism of traditional Chinese medicine in treating immune checkpoint inhibitor-induced colitis

Cancer ranks among the foremost causes of mortality worldwide, posing a significant threat to human lives. The advent of tumor immunotherapy has substantially transformed the therapeutic landscape for numerous advanced malignancies, notably non-small cell lung cancer and melanoma. However, as immune checkpoint inhibitors (ICIs) are increasingly applied in clinical settings, a spectrum of undesired reactions, termed immune-related adverse events (irAEs), has emerged. These adverse reactions are associated with immunotherapy and can result in varying degrees of harm to the human body. Among these reactions, Immune checkpoint inhibitor-induced colitis (ICIIC) stands out as one of the most prevalent clinical adverse events. In contemporary times, traditional Chinese medicine (TCM) has demonstrated remarkable efficacy in addressing various maladies. Consequently, investigating the potential application and mechanisms of Chinese medicine in countering immune checkpoint inhibitor-induced colitis assumes significant importance in the treatment of this condition.

Frequency of superantigen encoding genes of Staphylococcus aureus isolates collected from multiple sclerosis (MS) patients and nasal carriers

BACKGROUND

Bacterial superantigens are potent T cell activators that can have acute or chronic effects on the central nervous system.

OBJECTIVES

In this study, the role of enterotoxins, exfoliative toxins and toxic shock syndrome toxin of Staphylococcus aureus was investigated in MS patients and healthy nasal carriers.

METHODS

Three-hundred fifty nasal swabs were collected from healthy nasal carriers (n = 210) and MS (n = 140) patients. Staphylococcus aureus superantigens were detected by multiplex PCR. Antimicrobial susceptibility pattern was performed using disk diffusion method.

RESULTS

The highest rates of nasal colonization were seen in MS patients (46.42%). The rates of nasal colonization in the healthcare workers were 30.95%. The most commonly detected superantigens were SEA (31.5%), SEB (17.7%) and ETA (16.9%). The Staphylococcus aureus isolates had the highest levels of resistance against erythromycin (57.7%), clindamycin (55.4%) and co-trimoxazole (43.1%). All isolates were susceptible to vancomycin, linezolid, and mupirocin.

CONCLUSION

Our results revealed that the frequency of superantigen producing Staphylococcus aureus isolates is high in the MS patients. As well as these isolates are sensitive to mupirocin. Thus it is better to use of mupirocin for nasal decolonization of Staphylococcus aureus in the MS patients.

Clonal deletion of T cell repertoires with specific T cell receptor Vβ chains by two endogenous superantigens in NC/Nga mice

Superantigens (SAgs) are powerful T-cell stimulatory proteins. Because an atopic dermatitis (AD) model NC/Nga mice had two endogenous SAgs, namely minor lymphocyte-stimulating locus-1^a (Mls-1^a) and mouse mammary tumor virus (MMTV)(SHN), SAg-responsive T-cells bearing Vβ5.1, Vβ6, Vβ8.1, Vβ8.2, Vβ8.3, Vβ9, and Vβ11 should be endogenously deleted. Here, we discuss that the endogenous SAgs-expression may be involved in AD-sensitivity in NC/Nga mice.

Possible Role of Staphylococcal Enterotoxin B in the Pathogenesis of Autoimmune Diseases

As a member of superantigens (SAgs) produced by Staphylococcus aureus, staphylococcal enterotoxin B (SEB) is a exotoxin superantigen that can regulate the activity of immunomodulatory and pro-inflammatory cell types. In addition, SEB plays a critical role in the pathogenesis of autoimmune disorders either by initiating the autoimmune process or by inducing a relapse in an individual in clinical remission from an autoimmune disorder. SEB can directly activate T lymphocytes, leading to the release of cytokines, superoxides, or other mediators of inflammation either directly or indirectly, because of its unique ability to cross-link human major histocompatibility complex (MHC) class II and T cell receptors (TCR), forming a trimolecular complex. This review discusses the potential effects of SEB in the pathogenesis of autoimmune diseases such as multiple sclerosis, systemic lupus erythematosus, and rheumatoid arthritis, and explores some updated therapeutic medications to neutralize SEB.

Angiotensin converting enzyme-inhibitor reduces colitis severity in an IL-10 knockout model

BACKGROUND

We previously demonstrated angiotensin converting enzymes (ACE) over-expression in a dextran-sodium sulfate colitis model; ACE inhibitor (ACE-I) treatment reduced colitis severity in this model. However, ACE-I has not been tested in more immunologically relevant colitis models.

AIM

We hypothesized that ACE-I would decrease disease severity in an IL-10 knockout (-/-) colitis model.

METHODS

Colitis was induced by giving 10-week old IL-10-/- mice piroxicam (P.O.) for 14 days. The ACE-I enalaprilat was given transanally at a dose of 6.25 mg/kg for 21 days. Prednisolone (PSL) with or without enalaprilat were used as therapeutic, comparative groups. All groups were compared to a placebo treated group. Outcome measures were clinical course, histology, abundance of pro-inflammatory cytokines/chemokines, and epithelial barrier function.

RESULTS

Enalaprilat exhibited better survival (91 %) versus other treatment groups (PSL: 85.7 %, PSL + ACE-I: 71.4 %, placebo: 66.6 %). The ACE-I and PSL + ACE-I groups showed significantly better histological scores versus placebo mice. ACE-I and the PSL groups significantly reduced several pro-inflammatory cytokines versus placebo mice. FITC-dextran permeability was reduced in the ACE-I and PSL + ACE-I groups. Blood pressure was not affected in ACE-I treated mice compared to placebo mice.

CONCLUSIONS

ACE-I was effective in reducing severity of colitis in an IL-10-/- model. The addition of prednisolone minimally augmented this effect. The findings suggest that appropriately dosed ACE-I with or without steroids may be a new therapeutic agent for colitis.

Spontaneous autoimmune gastritis and hypochlorhydria are manifest in the ileitis-prone SAMP1/YitFcs mice

SAMP1/YitFcs mice serve as a model of Crohn's disease, and we have used them to assess gastritis. Gastritis was compared in SAMP1/YitFcs, AKR, and C57BL/6 mice by histology, immunohistochemistry, and flow cytometry. Gastric acid secretion was measured in ligated stomachs, while anti-parietal cell antibodies were assayed by immunofluorescence and enzyme-linked immunosorbent spot assay. SAMP1/YitFcs mice display a corpus-dominant, chronic gastritis with multifocal aggregates of mononuclear cells consisting of T and B lymphocytes. Relatively few aggregates were observed elsewhere in the stomach. The infiltrates in the oxyntic mucosa were associated with the loss of parietal cell mass. AKR mice, the founder strain of the SAMP1/YitFcs, also have gastritis, although they do not develop ileitis. Genetic studies using SAMP1/YitFcs-C57BL/6 congenic mice showed that the genetic regions regulating ileitis had comparable effects on gastritis. The majority of the cells in the aggregates expressed the T cell marker CD3 or the B cell marker B220. Adoptive transfer of SAMP1/YitFcs CD4(+) T helper cells, with or without B cells, into immunodeficient recipients induced a pangastritis and duodenitis. SAMP1/YitFcs and AKR mice manifest hypochlorhydria and anti-parietal cell antibodies. These data suggest that common genetic factors controlling gastroenteric disease in SAMP1/YitFcs mice regulate distinct pathogenic mechanisms causing inflammation in separate sites within the digestive tract.

Effect of TGF-beta1 on the expression of IL-12, IL-15, IL-18, IL-4 and IL-10 in heart transplantation rejection in rats

To investigate the effect of TGF-beta1 on the expressions of IL-12, IL-15, IL-18, IL-4 and IL-10 in heart transplantation rejection in rats, a model of rat cervical heterotopic heart transplantation was set up and the model rats were randomly divided into three groups: control group, transplant group and TGF-beta1 group. The mRNA expression levels of IL-12, IL-15, IL-18, IL-4 and IL-10 were determined by RT-PCR at the 5th day after the transplantation. The mRNA expression levels of IL-12, IL-15, IL-18 were increased obviously and those of IL-4, IL-10 were significantly decreased in the transplant group as compared with the control group (P<0.01). In the TGF-beta1 group, the mRNA expression levels of IL-12, IL-15, IL-18 were significantly decreased and those of IL-4, IL-10 were significantly increased as compared with the transplant group (P<0.01). The immunosuppressive effect of TGF-beta1 on heart transplantation rejection was related to its inhibition of the expressions of Th1-type cytokines (IL-12, IL-15, IL-18 etc) and its promotion of the expressions of Th2-type cytokines (IL-4, IL-10).

The interleukin-10 promoter haplotype ATA is a putative risk factor for aggressive periodontitis

BACKGROUND AND OBJECTIVE

Interleukin-10 has been described as an anti-inflammatory cytokine and a B-cell proliferation factor. Promoter polymorphisms of the interleukin-10 gene have been associated with altered interleukin-10 expression. Therefore, the aim of this study was to evaluate three polymorphisms at positions -1082G>A, -819C>T and -590C>A in patients with generalized chronic periodontitis (n = 27) and generalized aggressive periodontitis (n = 32) in comparison with periodontitis-free controls (n = 34).

MATERIAL AND METHODS

Interleukin-10 promoter polymorphisms were analyzed by polymerase chain reaction with sequence-specific primers (PCR-SSP). Distributions of single alleles, genotypes and haplotypes were calculated by the chi-square test. Risk factor analyses were carried out by logistic regression. Subgingival bacteria were subjected to molecular biological analyses using the micro-Ident test.

RESULTS

The combination ATA/ATA was found only in patients with aggressive periodontitis (15.6 vs. 0.0%, p = 0.023). Taking into account age, gender, smoking and plaque level, an increased odds ratio (3.7, p = 0.04) for aggressive periodontitis was shown for subjects with the haplotype ATA. Prevotella intermedia was found to be decreased in ACC- positive (41.3 vs. 66.7%, p = 0.022), ATA-positive (33.3 vs. 57.1%, p = 0.032) and ACC/ATA-positive (20.0 vs. 55.9%, p = 0.002) individuals. In GCC/GCC-positive subjects, P. intermedia occurred more frequently (86.7 vs. 42.3%, p = 0.002).

CONCLUSION

The haplotype ATA, which is known as a 'low interleukin-10 producer' is a putative risk indicator for generalized aggressive periodontitis.

The two faces of interleukin 10 in human infectious diseases

Resolution of infections depends on the host's ability to mount a protective immune response. However, an exacerbated response to infections may result in deleterious lesions. Consequently, immunoregulatory mechanisms are needed to control immune response and prevent infection-associated lesions. Interleukin 10 may be a major regulator of innate and adaptive immunity in vitro and in animals, but its role in human infections is still unclear. Review of the published work reveals wide involvement of interleukin 10 in two major features of infectious diseases. On one hand, interleukin 10 prevents the development of immunopathological lesions that result from exacerbated protective immune response to acute and chronic infections. On the other hand, it is critically involved in persistence of bacteria and viruses by interfering with innate and adaptive protective immunity. Moreover, infections induce the expansion of interleukin-10-producing regulatory cells that are involved in protection against allergic diseases.

Piroxicam treatment of IL-10-deficient mice enhances colonic epithelial apoptosis and mucosal exposure to intestinal bacteria

Treatment with the nonsteroidal anti-inflammatory drugs piroxicam or sulindac was recently shown to accelerate the development of colitis in interleukin (IL)-10-deficient (IL-10) mice. Although NSAIDs have been hypothesized to decrease the barrier function of the intestinal epithelium, the mechanism by which this accelerates colitis in IL-10 mice is not well understood. In this study, the effects of piroxicam on the colonic mucosa of IL-10 C57BL/6 mice were evaluated histologically. The effect of piroxicam on intestinal epithelial cells in vitro was assessed using colorimetric and fluorescent assays for cell viability and apoptotic cell death. Interactions of intestinal bacteria with the colonic mucosa were evaluated by rRNA-directed fluorescence in situ hybridization. In vivo treatment of C57BL/6 IL-10 mice with oral piroxicam markedly enhanced apoptosis of colonic epithelium and resulted in focal erosion of the mucosal surface, enhanced bacterial adhesion and invasion, and accelerated the development of colitis. In vitro, piroxicam induced apoptosis of CT26 murine intestinal epithelial cells in a dose-dependent fashion. Piroxicam-induced apoptosis of CT26 cells could not be prevented by addition of exogenous IL-10; however, IL-10 did significantly enhance their rate of proliferation. Thus, exposure to piroxicam enhances intestinal epithelial apoptosis both in vitro and in vivo and facilitates adhesion and invasion of intestinal bacteria into mucosal tissues in vivo. The role of IL-10 in this process requires further study. These studies support the hypothesis that increased exposure of mucosal cells to intestinal bacteria may lead to development of intestinal inflammation in IL-10 or other genetically susceptible individuals.

IL-10 modulates intestinal damage and epithelial cell apoptosis in T cell-mediated enteropathy

In vivo T cell activation by anti-CD3 monoclonal antibody (mAb) results in intestinal damage characterized by loss of villi and epithelial cell apoptosis. The role of the increased interleukin (IL)-10 released during this process is not clear. We assessed the effects of IL-10 on T cell-induced mucosal damage in vivo using IL-10-deficient C57BL/6 [IL-10 knockout (KO)] mice. IL-10 KO and wild-type C57BL/6 mice were injected with anti-CD3 mAb and observed for diarrhea. Changes in serum cytokine levels were measured by ELISA. Histological changes and epithelial cell apoptosis were analyzed on hematoxylin- and eosin-stained tissue sections. Fas expression on intestinal epithelial cells was assessed by flow cytometry analysis of freshly isolated intestinal epithelial cells. Anti-CD3-treated IL-10 KO mice developed more severe diarrhea, a greater loss of intestinal villi, and an increase in the numbers of apoptotic cells in the crypt epithelium. This difference in IL-10 KO mice was associated with an increase in serum tumor necrosis factor-alpha and interferon-gamma levels and with an increase in Fas expression on fresh, isolated, small intestinal epithelial cells. In addition, the enhanced intestinal tissue damage induced by anti-CD3 in IL-10 KO mice was significantly diminished by treatment with recombinant murine IL-10. Therefore, the lack of IL-10 allowed for an increased T cell-induced intestinal tissue damage, and this was associated with an increase in T cell cytokine release and an increase in epithelial cell Fas expression.

Rho GTPase is activated by cytotoxic necrotizing factor 1 in peripheral blood T lymphocytes: potential cytotoxicity for intestinal epithelial cells

Some strains of Escherichia coli related to acute cystitis or colitis produce a toxin named cytotoxic necrotizing factor 1 (CNF-1). CNF-1 mediates its effects on epithelial cells or phagocytes via the permanent activation of small GTP-binding proteins, caused by the toxin-induced deamidation of Glu(63) of p21 Rho. The behavior of peripheral blood T lymphocytes during the acute phase of bacterial colitis has been poorly investigated. Our study was conducted to test whether (i) peripheral blood T lymphocytes can be activated by CNF-1 and (ii) CNF-1-activated T lymphocytes are cytotoxic against intestinal epithelial cells. Activation of T lymphocytes by CNF-1 was assessed by electrophoresis, flow cytometry, confocal microscopy, and electron microscopy studies. Assays for migration and adherence of CNF-1-treated T lymphocytes were performed in Transwell chambers with T84 intestinal epithelial cells grown on polycarbonate semipermeable filters. CNF-1 induced a decrease in the electrophoretic mobility of the GTP-binding protein Rho in treated T lymphocytes. CNF-1 provoked an increase in the content of actin stress fibers and pseudopodia in T lymphocytes. Several adherence molecules were clustered into cytoplasmic projections in CNF-1-treated T lymphocytes and adherence of such lymphocytes on the basolateral pole of T84 was increased, resulting in cytotoxicity toward epithelial cells. Such enhanced adherence in response to CNF-1 was dependent on p42-44(MAP) kinase activation of T lymphocytes. Taken together, these results suggest that CNF-1, by acting on T lymphocytes, may increase in an important fashion the virulence of certain strains of E. coli against the intestinal epithelia.

Oxidative stress induces the expression of Fas and Fas ligand and apoptosis in murine intestinal epithelial cells

Intestinal epithelial cell function is compromised by local immune and inflammatory responses. In this study, we examined the possibility that intestinal epithelial cell injury occurs in the presence of activated inflammatory cells, such as neutrophils and macrophages, via production of reactive oxygen species (ROS). Following exposure to 50-150 microM H2O2 levels of mRNA and protein for Fas and, to a lesser degree, Fas-L were increased and intestinal epithelial cells underwent apoptosis. Treatment of H2O2-exposed cells with agonistic anti-Fas antibody, but not isotype control antibody, significantly enhanced apoptosis. Apoptosis was associated with the activation of caspase 8, while Z-IETD, an inhibitor of caspase 8, blocked apoptosis of H2O2-exposed intestinal epithelial cells. Thus, ROS induced Fas and Fas-L expression in association with intestinal epithelial cell apoptosis. These data support the hypothesis that, following exposure to oxidative stress, enterocytes are primed for cell death via Fas-mediated pathways.

Microbiological and immunological strategies for treatment of inflammatory bowel disease

Chronic inflammatory bowel diseases such as Crohn's disease or ulcerative colitis, affect around 1 in every 1000 individuals in western countries. They probably result from an inappropriate reaction towards the commensal microflora and are currently treated with anti-inflammatory drugs or surgery. Novel strategies aim at blocking lymphocyte recruitment and activation, improved targeting of therapeutics and modification of gut microflora.

Interleukin-10 and apoptotic death of circulating lymphocytes in surgical/anesthesia trauma

OBJECTIVE

To examine the relationship between circulating interleukin-10 (IL-10) and the occurrence of lymphocyte apoptosis after surgical/anesthesia trauma.

METHODS

Data were collected prospectively on 18 adult patients undergoing elective major surgery. Blood sampling for assessment of lymphocyte apoptosis and IL-10 levels was performed on the day before surgery (t(0)) and at 24 and 96 hours after operation (t(1) and t(2), respectively). After lymphocyte isolation, quantification of apoptosis was made by staining apoptotic cells with 7-amino-actinomycin D. Plasma IL-10 concentrations were measured using enzyme-linked immunosorbent assay.

RESULTS

A significantly increased frequency of apoptotic CD4(+) and CD8(+) cells (p < 0.05) was observed at t1 measurement (8.10% +/- 0.58% and 12.21% +/- 1.47% for CD4(+) and CD8(+), respectively) compared with preoperative values (1.53% +/- 0.38% and 1.32% +/- 0.45% for CD4(+) and CD8(+), respectively). Plasma IL-10 levels showed a significant elevation at both t(1) and t(2) times, peaking at t(1). At t(1), IL-10 levels were correlated with the frequency of CD4(+) and CD8(+) apoptotic lymphocytes (r = 0.78, p = 0.0005 for IL-10 vs. apoptotic CD4(+); r = 0.71, p = 0.003 for IL-10 vs. apoptotic CD8(+)).

CONCLUSION

Surgical trauma is associated with a significant but transient increase in lymphocyte commitment to apoptosis and IL-10 production. The exact relationship linking the overproduction of IL-10 with lymphocyte apoptosis after a surgical operation is still elusive and requires further investigation.