Reciprocal effects of IFN-beta and IL-12 on STAT4 activation and cytokine induction in T cells

An immunomodulating peptide with potential to suppress tumour growth and autoimmunity

Cancers and autoimmune diseases commonly co-exist and immune checkpoint inhibitor therapy (ICI) exacerbates autoimmune pathologies. We recently described a lipidic peptide, designated IK14004, that promotes expansion of immunosuppressive T regulatory (Treg) cells and uncouples interleukin-2 from interferon-gamma production while activating CD8+ T cells. Herein, we report IK14004-mediated inhibition of Lewis lung cancer (LLC) growth and re-invigoration of splenocyte-derived exhausted CD4+ T cells. In human immune cells from healthy donors, IK14004 modulates expression of the T cell receptor α/β subunits, induces Type I IFN expression, stimulates natural killer (NK) cells to express NKG2D/NKp44 receptors and enhances K562 cytotoxicity. In both T and NK cells, IK14004 alters the IL-12 receptor β1/β2 chain ratio to favour IL-12p70 binding. Taken together, this novel peptide offers an opportunity to gain further insight into the complexity of ICI immunotherapy so that autoimmune responses may be minimised without promoting tumour evasion from the immune system.

Toxocara canis extract fractions promote mainly the production of Th1 and regulatory cytokines by human leukocytes in vitro

Helminths possibly down-modulate immune responses to airborne allergens through the induction of a regulatory network. The identification of helminths bioactive molecules is highly desirable, given their immunomodulatory potential which could be used in immunotherapies for allergy and autoimmune diseases. To investigate the immunoregulatory potential of the adult Toxocara canis crude extract and ten protein fractions of its extract, human peripheral blood mononuclear cells (PBMC) from 10 allergic and 9 non-allergic individuals were cultivated, in vitro, in the presence or absence of these antigens, and their supernatants were evaluated for cytokine production (TGF-β, IL-10, IL-12, TNF-α, IL-6, IL-5, IL13, and IL-17). To determine the cell viability, the PBMC were cultivated for 24 h in the presence of the antigens and, following, they were subjected to a cytotoxicity assay. The viability of the PBMC was not affected by incubation with the T. canis antigens. As some fractions stimulated the production of immunoregulatory (TGF-β and/or IL-10), IL-12 and Th1 (TNF-α) cytokines, without stimulating Th2 cytokines (IL-5 and IL13) and IL-17, it was proposed that they would be potential candidates for further studies, especially involving the purification and characterization of specific proteins, which could be tested separately to evaluate their specific role as adjuvants in immunotherapy for inflammatory diseases.

Decreased interferon-β induced STAT-4 activation in immune cells and clinical outcome in multiple sclerosis

OBJECTIVES

Interferon-β (IFN-β) is used in the treatment of multiple sclerosis (MS). IFN-β activation of signal transduction and activation of transcription (STAT)-4 is linked to its immunomodulatory effects. Previous studies suggest a type I IFN deficit in immune cells of patients MS, but data on interferon-α/β receptor (IFNAR) expression and the relationship with treatment response are conflicting. Here, we compare IFN-β-mediated STAT4 activation in immune cells of untreated patients with MS and controls.

MATERIALS AND METHODS

Peripheral blood mononuclear cells from 27 untreated patients with relapsing MS, obtained before the initiation of IFN-β treatment, and 12 matched controls were treated in vitro with IFN-β. Total and phosphorylated STAT4 (pSTAT4) and IFNAR were measured by flow cytometry and quantitative PCR. The patients were followed up for 5 years.

RESULTS

pSTAT4 induction by IFN-β was lower in patients with MS than in controls, as was expression of IFNAR. pSTAT4 expression did not correlate with the clinical outcome at 5 years, measured by EDSS change. There was a negative correlation between the baseline IFNAR1 mRNA levels and relapse rate.

CONCLUSIONS

The results suggest decreased IFN-β responsiveness in patients with MS, associated with reduced STAT4 activation and reduced IFNAR expression. This reduced responsiveness does not appear to affect the long-term clinical outcome of IFN-β treatment.

Higher expression of IL-12Rβ2 is associated with lower risk of relapse in relapsing-remitting multiple sclerosis patients on interferon-β1b therapy during 3-year follow-up

Cytokines produced by helper T (Th)1 cells, Th17 and regulatory T cells (Treg) are involved in multiple sclerosis (MS) immunopathogenesis. Interferon (IFN)-β alters the numerous genes' expression, but how this alteration affects the treatment response is still elusive. We assessed relative gene expression of nineteen Th1/Th17/Treg-associated mediators in peripheral blood mononuclear cells and plasma levels of GM-CSF, IL-17A and IL-17F, in relapsing-remitting MS (RRMS) patients before IFN-β1b treatment initiation and at 6, 12, 24 and 36 months of therapy. All mRNA levels changed significantly during the IFN-β1b therapy. Higher IL-12Rβ2 mRNA levels were associated with lower risk of relapse. Despite recent reports regarding role of GM-CSF in MS, our study failed to demonstrate its significance as therapy response biomarker, both on the mRNA and protein level.

Interleukin-10 and interleukin-12 modulation in patients with relapsing-remitting multiple sclerosis on therapy with interferon-beta 1a: differences in responders and non responders

We examined the effects of interferon (IFN)beta-1a on interleukin (IL)-12p70 and IL-10 secretion in 27 Relapsing Remitting Multiple Sclerosis (RRMS) patients, divided in responders and non-responders. In responders, IFNbeta-1a does not change the IL-12p70 concentrations, but it leads to a remarkable increase in the IL-10 production. Besides, a high IL-10/IL-12 ratio is demonstrated during the first six months of therapy. In non-responders, there were not significant alterations in the cytokine profile. We suggest that IFNbeta-1a effect in RRMS patients could be explained by its modifying effect on cytokine pattern. Moreover, we propose a possible role of IL-10/IL-12 ratio as a serum marker predictive of favorable clinical course.

New insights into the roles of Stat5a/b and Stat3 in T cell development and differentiation

T cell development and differentiation is carefully orchestrated by a series of cytokines. The importance of STAT family proteins in mediating signals by these cytokines is well-known, but new information on the role of STATs in novel aspects of T cell function and T cell subsets continues to accumulate. Recent studies have placed Stat5a/b and Stat3 center stage in T cell development and differentiation. Stat5a/b are indispensable in T regulatory (Treg) cell development and maintenance, and negatively regulate T helper 17 (Th17) cell differentiation. Conversely, Stat3 is essential for Th17 differentiation and inhibits Treg cells. The balance of Treg and Th17 cells is thought to be critical in maintaining immune tolerance, while preserving effective host defense. Therefore, Stat5a/b and Stat3 are emerging to be key players in T cell differentiation and homeostasis.