Ocrelizumab Alters Cytotoxic Lymphocyte Function While Reducing EBV-Specific CD8+ T-Cell Proliferation in Patients With Multiple Sclerosis.

BACKGROUND AND OBJECTIVES: The role of B cells in the pathogenic events leading to relapsing multiple sclerosis (R-MS) has only been recently elucidated. A pivotal step in defining this role has been provided by therapeutic efficacy of anti-CD20 monoclonal antibodies. Indeed, treatment with anti-CD20 can also alter number and function of other immune cells not directly expressing CD20 on their cell surface, whose activities can contribute to unknown aspects influencing therapeutic efficacy. We examined the phenotype and function of cytotoxic lymphocytes and Epstein-Barr virus (EBV)-specific immune responses in people with R-MS before and after ocrelizumab treatment. METHODS: In this prospective study, we collected blood samples from people with R-MS (n = 41) before and 6 and 12 months after initiating ocrelizumab to assess the immune phenotype and the indirect impact on cytotoxic functions of CD8+ T and NK cells. In addition, we evaluated the specific anti-EBV proliferative responses of both CD8+ T and NK lymphocytes as surrogate markers of anti-EBV activity. RESULTS: We observed that while ocrelizumab depleted circulating B cells, it also reduced the expression of activation and migratory markers on both CD8+ T and NK cells as well as their in vitro cytotoxic activity. A comparable pattern in the modulation of immune molecules by ocrelizumab was observed in cytotoxic cells even when patients with R-MS were divided into groups based on their prior disease-modifying treatment. These effects were accompanied by a significant and selective reduction of CD8+ T-cell proliferation in response to EBV antigenic peptides. DISCUSSION: Taken together, our findings suggest that ocrelizumab-while depleting B cells-affects the cytotoxic function of CD8+ and NK cells, whose reduced cross-activity against myelin antigens might also contribute to its therapeutic efficacy during MS.

Signals of pseudo-starvation unveil the amino acid transporter SLC7A11 as key determinant in the control of Treg cell proliferative potential.

Human CD4+CD25hiFOXP3+ regulatory T (Treg) cells are key players in the control of immunological self-tolerance and homeostasis. Here, we report that signals of pseudo-starvation reversed human Treg cell in vitro anergy through an integrated transcriptional response, pertaining to proliferation, metabolism, and transmembrane solute carrier transport. At the molecular level, the Treg cell proliferative response was dependent on the induction of the cystine/glutamate antiporter solute carrier (SLC)7A11, whose expression was controlled by the nuclear factor erythroid 2-related factor 2 (NRF2). SLC7A11 induction in Treg cells was impaired in subjects with relapsing-remitting multiple sclerosis (RRMS), an autoimmune disorder associated with reduced Treg cell proliferative capacity. Treatment of RRMS subjects with dimethyl fumarate (DMF) rescued SLC7A11 induction and fully recovered Treg cell expansion. These results suggest a previously unrecognized mechanism that may account for the progressive loss of Treg cells in autoimmunity and unveil SLC7A11 as major target for the rescue of Treg cell proliferation.

Caloric Restriction Promotes Immunometabolic Reprogramming Leading to Protection from Tuberculosis.

There is a strong relationship between metabolic state and susceptibility to Mycobacterium tuberculosis (MTB) infection, with energy metabolism setting the basis for an exaggerated immuno-inflammatory response, which concurs with MTB pathogenesis. Herein, we show that controlled caloric restriction (CR), not leading to malnutrition, protects susceptible DBA/2 mice against pulmonary MTB infection by reducing bacterial load, lung immunopathology, and generation of foam cells, an MTB reservoir in lung granulomas. Mechanistically, CR induced a metabolic shift toward glycolysis, and decreased both fatty acid oxidation and mTOR activity associated with induction of autophagy in immune cells. An integrated multi-omics approach revealed a specific CR-induced metabolomic, transcriptomic, and proteomic signature leading to reduced lung damage and protective remodeling of lung interstitial tightness able to limit MTB spreading. Our data propose CR as a feasible immunometabolic manipulation to control MTB infection, and this approach offers an unexpected strategy to boost immunity against MTB.

Differential impact of high and low penetrance TNFRSF1A gene mutations on conventional and regulatory CD4+ T cell functions in TNFR1-associated periodic syndrome.

TNFR-associated periodic syndrome is an autoinflammatory disorder caused by autosomal-dominant mutations in TNFRSF1A, the gene encoding for TNFR superfamily 1A. The lack of knowledge in the field of TNFR-associated periodic syndrome biology is clear, particularly in the context of control of immune self-tolerance. We investigated how TNF-α/TNFR superfamily 1A signaling can affect T cell biology, focusing on conventional CD4(+)CD25(-) and regulatory CD4(+)CD25(+) T cell functions in patients with TNFR-associated periodic syndrome carrying either high or low penetrance TNFRSF1A mutations. Specifically, we observed that in high penetrance TNFR-associated periodic syndrome, at the molecular level, these alterations were secondary to a hyperactivation of the ERK1/2, STAT1/3/5, mammalian target of rapamycin, and NF-κB pathways in conventional T cells. In addition, these patients had a lower frequency of peripheral regulatory T cells, which also displayed a defective suppressive phenotype. These alterations were partially found in low penetrance TNFR-associated periodic syndrome, suggesting a specific link between the penetrance of the TNFRSF1A mutation and the observed T cell phenotype. Taken together, our data envision a novel role for adaptive immunity in the pathogenesis of TNFR-associated periodic syndrome involving both CD4(+) conventional T cells and Tregs, suggesting a novel mechanism of inflammation in the context of autoinflammatory disorders.

Human lung-resident macrophages express CB1 and CB2 receptors whose activation inhibits the release of angiogenic and lymphangiogenic factors.

Macrophages are pivotal effector cells in immune responses and tissue remodeling by producing a wide spectrum of mediators, including angiogenic and lymphangiogenic factors. Activation of cannabinoid receptor types 1 and 2 has been suggested as a new strategy to modulate angiogenesis in vitro and in vivo. We investigated whether human lung-resident macrophages express a complete endocannabinoid system by assessing their production of endocannabinoids and expression of cannabinoid receptors. Unstimulated human lung macrophage produce 2-arachidonoylglycerol,N-arachidonoyl-ethanolamine,N-palmitoyl-ethanolamine, and N-oleoyl-ethanolamine. On LPS stimulation, human lung macrophages selectively synthesize 2-arachidonoylglycerol in a calcium-dependent manner. Human lung macrophages express cannabinoid receptor types 1 and 2, and their activation induces ERK1/2 phosphorylation and reactive oxygen species generation. Cannabinoid receptor activation by the specific synthetic agonists ACEA and JWH-133 (but not the endogenous agonist 2-arachidonoylglycerol) markedly inhibits LPS-induced production of vascular endothelial growth factor-A, vascular endothelial growth factor-C, and angiopoietins and modestly affects IL-6 secretion. No significant modulation of TNF-α or IL-8/CXCL8 release was observed. The production of vascular endothelial growth factor-A by human monocyte-derived macrophages is not modulated by activation of cannabinoid receptor types 1 and 2. Given the prominent role of macrophage-assisted vascular remodeling in many tumors, we identified the expression of cannabinoid receptors in lung cancer-associated macrophages. Our results demonstrate that cannabinoid receptor activation selectively inhibits the release of angiogenic and lymphangiogenic factors from human lung macrophage but not from monocyte-derived macrophages. Activation of cannabinoid receptors on tissue-resident macrophages might be a novel strategy to modulate macrophage-assisted vascular remodeling in cancer and chronic inflammation.

Simplexide induces CD1d-dependent cytokine and chemokine production from human monocytes.

Monocytes are major effector cells of innate immunity and recognize several endogenous and exogenous molecules due to the expression of wide spectrum of receptors. Among them, the MHC class I-like molecule CD1d interacts with glycolipids and presents them to iNKT cells, mediating their activation. Simplexide belongs to a novel class of glycolipids isolated from marine sponges and is structurally distinct from other immunologically active glycolipids. In this study we have examined the effects of simplexide on cytokine and chemokine release from human monocytes. Simplexide induces a concentration- and time-dependent release of IL-6, CXCL8, TNF-α and IL-10 and increases the expression of IL6, CXCL8 and IL10 mRNA. Cytokine and chemokine release induced by simplexide from monocytes is dependent on CD1d since: i) a CD1d antagonist, 1,2-bis (diphenylphosphino) ethane [DPPE]-polyethylene glycolmonomethylether [PEG], specifically blocks simplexide-induced activation of monocytes; ii) CD1d knockdown inhibits monocyte activation by simplexide and iii) simplexide induces cytokine production from CD1d-transfected but not parental C1R cell line. Finally, we have shown that simplexide also induces iNKT cell expansion in vitro. Our results demonstrate that simplexide, apart from activating iNKT cells, induces the production of cytokines and chemokines from human monocytes by direct interaction with CD1d.