Effects of an anti-IL-10 monoclonal antibody on rIFNbeta-1b-mediated immune modulation. Relevance to multiple sclerosis

Targeting IL-10 in auto-immune diseases

IL-10 is a multifunctional cytokine secreted by a variety of cells. It not only inhibits activation of monocyte/macrophage system and synthesis of monocyte cytokine and inflammatory cytokine but also promotes the proliferation and maturation of non-monocyte-dependent T cell, stimulating proliferation of antigen-specific B cell. Increasing evidence indicates that IL-10 plays an important role in both the onset and development of auto-immune diseases, such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), Sjogren's syndrome (SS), multiple sclerosis (MS), Crohn's disease (CD), and psoriasis. However, the exact mechanisms of IL-10 in auto-immune diseases remain unclear. In the present review, we will summarize the biological effects of IL-10, as well as its role and therapeutic potential in auto-immune diseases.

Giving monoclonal antibodies to healthy volunteers in phase 1 trials: is it safe?

Many monoclonal antibodies (MAbs) have been studied in healthy volunteers in phase 1, but few data have been published on the safety of that practice. We aimed to review the available data, and thereby to estimate the risks of participation in phase 1trials of MAbs. We searched PubMed, the ClinicalTrials.gov database and Google, using the search terms 'monoclonal antibody', 'phase 1' and 'healthy volunteers'. We identified 70 completed trials of MAbs in healthy volunteers, but the published data were too sparse to allow confident assessment of the risks of MAbs in healthy volunteers. Our best estimate of risk of a life-threatening adverse event was between 1: 425 and 1: 1700 volunteer-trials, but all such events occurred in a single trial (of TGN1412). In a phase 1trial of a small molecule, the risk of death or a life-threatening adverse event appears to be 1: 100,000-1,000,000 volunteer-trials, which is similar to the risk of many ordinary daily activities. Most people would consider that level of risk to be 'minimal' or 'negligible' and, therefore, acceptable. On that basis, the safety record of MAbs in healthy volunteers has been ruined by the TGN1412 disaster. However, that experience is unlikely to be repeated, because of improvements in governance and practice of phase 1trials. If the experience of TGN1412 is disregarded, it seems reasonable to continue using healthy volunteers in phase 1trials of MAbs, provided that there are scientific and medical reasons to conclude that the risk is truly minimal.

Treatment with an acetylcholinesterase inhibitor in Alzheimer patients modulates the expression and production of the pro-inflammatory and anti-inflammatory cytokines

Elevated levels of cytokines have been detected in brains of Alzheimer's disease (AD) patients, and altered peripheral levels of IL-1beta, TNFalpha and IL-6 have been reported in these patients. We studied the ability of PBMC from patients with AD, matched with a control group, to release pro- and anti-inflammatory cytokines, and the effect of AChEI treatment on cytokine release. Our data indicates that AChEI treatment down-regulates IL-1, IL-6 and TNF, and up-regulates the expression and production of IL-4 in PBMC in AD patients, and that AChEI leads to the remodelling of the cytokine network, probably acting on the lymphocytic cholinergic system.

Monocyte-derived IL12, CD86 (B7-2) and CD40L expression in relapsing and progressive multiple sclerosis

Multiple sclerosis has been postulated to be an autoimmune disease in which Th1 immune responses predominate. This response is associated with an increased production of IFNgamma and IL12 produced by T cells and by cells of the monocyte (MO) lineage, respectively. An increased expression of costimulatory molecules by T cells and antigen-presenting cells is also observed. We hypothesized that in relapsing-remitting MS (RRMS) (with or without of IFNbeta treatment) and in secondary progressive patients (SPMS) IL12 and costimulatory molecules (CD80 [B7-1], CD86 [B7-2], CD28, CD40, CD40L) would be differentially produced or expressed by MO or T cells. We performed cross-sectional and longitudinal flow cytometric studies (at monthly intervals) on peripheral blood mononuclear cells (PBMC) or on MO from SPMS or untreated and IFNbeta-treated patients with RRMS. We determined that CD86 and CD40L expression was highest on MO derived from SPMS patients compared to those from RRMS or from healthy controls (HC). In vitro culture of PBMC with recombinant human IL10, a cytokine that may be increased in response to treatment with IFNbeta and that down-regulates CD86 expression, reduced the expression of CD86 on MO derived from RRMS patients to a much higher degree compared to cells derived from SPMS or HC. In vitro secreted IL12 levels from freshly isolated MO from SPMS patients were more than 10-fold higher than either the treated or the untreated RRMS or HC. RRMS patients treated with IFNbeta demonstrated slightly lower levels of MO IL12 secretion. Our data suggest that a key mechanism in the pathogenesis of MS is the increased expression of CD86 and CD40L and the increased production of IL12 during disease progression. Part of the mechanism of action of IFNbeta may be to reduce MO CD86 and CD40L expression and IL12 secretion; failure to do so might signify either a lack of response or a transition to a more progressive phase of illness.

IFN-beta inhibits the ability of T lymphocytes to induce TNF-alpha and IL-1beta production in monocytes upon direct cell-cell contact

Tumour necrosis factor (TNF)-alpha and interleukin (IL-)1beta, essential players in the pathogenesis of immuno-inflammatory diseases, are strongly induced in monocytes by direct contact with stimulated T lymphocytes. The present study shows that the latter mechanism is inhibited by interferon (IFN)-beta. In co-cultures of autologous T lymphocytes and monocytes stimulated by phytohaemagglutinin (PHA), IFN-beta inhibited the production of TNF-alpha and IL-1beta by 88 and 98%, respectively, whereas the simultaneous production of IL-1 receptor antagonist (IL-1Ra), was enhanced two-fold. The latter effects of IFN-beta were independent of modulations in IFN-gamma, IL-4 and IL-10 production. When monocytes were activated by plasma membranes of stimulated T cells, IFN-beta slightly inhibited the production of TNF-alpha and IL-1beta, while enhancing 1.5-fold that of IL-1Ra. The latter effect correlated with the persistence of high steady-state levels of IL-1Ra mRNA after 24 h of activation. Membranes isolated from T lymphocytes that had been stimulated in the presence of IFN-beta displayed a 80% decrease in their capacity to induce the production of IL-1beta and TNF-alpha in monocytes, whereas IL-1Ra induction was decreased by only 32%. These results demonstrate that IFN-beta modulates contact-mediated activation of monocytes by acting on both T lymphocytes and monocytes, decreasing the ability of T lymphocytes to induce TNF-alpha and IL-1beta production in monocytes and directly enhancing the production of IL-1Ra in the latter cells.

Interferon-beta induces selective enhancement of antigen-specific T cell responses

Interferon-beta (IFN-beta) inhibits mitogen-induced T cell responses, in part through downregulation of interleukin-12 (IL-12) or upregulation of IL-10. We have reexamined these findings using ragweed (RW) stimulated or tetanus toxoid (TT)-stimulated human peripheral blood mononuclear cells (PBMC) and nontransformed, antigen-specific, human Th0, Th1, and Th2 clones. IFN-beta induced concentration-dependent inhibition of phytohemagglutinin (PHA)-stimulated PBMC proliferation and enhancement of RW-stimulated or TTstimulated PBMC proliferation. Monocyte depletion of PBMC isolates resulted in concentration-dependent inhibition of RW-driven or TT-driven proliferation by IFN-beta. This response was unaltered by the addition of either exogenous recombinant human IL-12 (rHuIL-12) or saturating concentrations of anti-IL-10. Moreover, addition of exogenous rHuIL-10 to nondepleted RW-driven or TT-driven PBMC cultures did not alter the concentration-dependent enhancement of antigen-driven proliferation induced by IFN-beta. Th0, Th1, and Th2 clones stimulated in the presence of antigen and autologous, irradiated PBMC displayed concentration-dependent inhibition of proliferation in the presence of IFN-beta that was unaltered by the addition of either exogenous rHuIL-12 or a saturating concentration of anti-IL-10. Finally, whereas IFN-beta inhibited antigen-driven generation of IL-5, IL-12, IL-13, and IFN-gamma, IFN-beta enhanced generation of both IL-4 and IL-10. Thus, IFN-beta, induces a selective, IL-10-independent and IL-12-independent upregulation of antigen-specific T cell responses, supporting the role of IFN-beta as an immunomodulatory rather than an antiproliferative/immunosuppressive cytokine.

Interferon (IFN)-beta treatment enhances CD95 and interleukin 10 expression but reduces interferon-gamma producing T cells in MS patients

Interferon (IFN)-beta has been shown to favorably alter the disease course of relapsing-remitting multiple sclerosis (RRMS) patients. Although its mode of action is still unclear, there is ample evidence from in vitro studies that IFN-beta directly modulates the function of immune cells. We analyzed here the effects of IFN-beta treatment on immune functions in vivo in a group of 25 RRMS patients who received IFN-beta (8 MIU) on alternate days. At baseline and at 1, 3 and 6 months from the start of the treatment, parameters for differentiation and activation states of both monocytes and T lymphocytes were assessed. A transient increase was seen in plasma (p) interleukin (IL)-10 level whereas pIL-12 (p40) was not affected. A similar change was found in the ability of monocytes to secrete these cytokines in vitro. Notably, patients who in vitro readily responded to IFN-beta with enhanced IL-10 production had the highest pIL-10 levels. Concerning T-cell differentiation, flow cytometric analysis of cytokine production showed that treatment with IFN-beta moderately decreased the mean percentages of CD8pos T cells producing IL-2 and IFN-gamma and CD8neg T cells producing IL-4 (p<0.05 for all cytokines), whereas a more significant decline was seen in the mean percentage of CD8neg T cells producing IFN-gamma (p<0.01). This resulted in a significant lower ratio T(HELPER(H))1 vs. T(HELPER(H))2 type cells in the CD8pos T-cell subset (p<0.05), but not in the CD8neg T-cell subset. Finally, IFN-beta treatment resulted in an initial rise in the mean percentage of CD95pos T cells and in a gradual increase in the mean level of soluble CD95 (sCD95) in plasma (p<0.01). Additional in vitro studies showed that IFN-beta indeed rapidly (within 24 h) upregulates CD95 expression on both primed and unprimed T cells and augments the release of sCD95 in culture supernatants. Thus, we confirm here that IFN-beta treatment leads to similar changes in cytokine production of T cells and monocytes as previously described in vitro. Enhanced IL-10 secretion may downmodulate cytokine secretion by activated T cells and in this way dampen newly-induced and/or ongoing immune responses. In addition, we identified a novel effect of IFN-beta treatment, i.e., induction of CD95 expression. The augmentation of CD95 expression may directly interfere with T-cell selection, notably of autoaggressive T cells. Future studies are needed to show whether this increased CD95 expression indeed leads to increased apoptosis of immune cells.