[Show abstract][Hide abstract] ABSTRACT: Interferon lambda-1 (IFN-lambda1/IL-29) is a member of the Type-III interferon family, which contains three ligands: IFN-lambda1, 2 and 3. These three ligands use the same unique heterodimeric receptor composed of CRF2-12 (IFN-lambda-R1/IL-28Ralpha) and CRF2-4 (IL10-R-beta) chains. Like their close relatives, the Type-I interferons, IFN-lambda1, 2 and 3, promote the phosphorylation of STAT1 and STAT2, induce the ISRE3 complex, elevate OAS and MxA expression and exhibit antiviral activity in vitro. Their use of the IL10-R-beta chain and their ability to phosphorylate STAT3, STAT4 and STAT5 suggested that they may also exhibit immunomodulatory activity; their antiviral action led us to hypothesize that this activity might be directed toward the Th1/Th2 system. Here, we have demonstrated that IFN-lambda1 altered the activity of Th cells in three separate experimental systems: (i) mitogen stimulation, (ii) mixed-lymphocyte reaction (MLR) and (iii) stimulation of naive T cells by monocyte-derived dendritic cells (mDC). In Con-A stimulation assays, the inclusion of IFN-lambda1 consistently led to markedly diminished levels of secreted interleukin (IL-13) with occasional coincident, modest elevation of secreted IFN-gamma. IL-13 secretion was 100-fold more sensitive to IFN-lambda1 than was IFN-gamma secretion. These observations were also made in the allogeneic two-way MLR. IFN-lambda1 was able to alter cytokine-mediated Th biasing and when naive T cells were exposed to allogeneic mDC that had been matured in the presence of IFN-lambda1, secreted IL-13 was again markedly and consistently reduced, whereas secreted IFN-gamma was largely unaltered. These functions were independent of IL-10. Our data support a hitherto unsuspected role for IFN-lambda1 in modulating the development of Th1 and Th2 cells, with an apparent emphasis on the diminution of IL-13 secretion.
Full-text · Article · May 2007 · Genes and Immunity
[Show abstract][Hide abstract] ABSTRACT: The interferon lambda family (IFN-lambda1/2/3) is a newly described group of cytokines that are related to both the type-1 interferons and IL-10 family members. These novel cytokines are induced during viral infection and, like type-1 interferons, display significant anti-viral activity. In order to understand their function in more depth, we have examined the ability of IFN-lambda1/IL-29 to regulate cytokine production by human immune cells. Whole peripheral blood mononuclear cells (PBMC) exposed to IFN-lambda1 specifically upregulated IL-6, -8 and -10 but there were no visible effects on TNF or IL-1. This response was produced in a dose-dependant fashion and was inhibited by IL-10. Examination of purified cell populations isolated from PBMC demonstrated that monocytes, rather than lymphocytes, were the major IFN-lambda1-responsive cellular subset, producing IL-6, -8 and -10 in response to IFN-lambda1. Monocyte responses induced by low-level LPS stimulation were also synergistically enhanced by the presence of IFN-lambda1. Human macrophages were also shown to react to IFN-lambda1 similarly to monocytes, by producing the cytokines IL-6, -8 and -10. In conclusion, we have shown that IFN-lambda1, a cytokine produced in response to viral infection, activates both monocytes and macrophages producing a restricted panel of cytokines and may therefore be important in activating innate immune responses at the site of viral infection.
Full-text · Article · Feb 2007 · Genes and Immunity
[Show abstract][Hide abstract] ABSTRACT: Interleukin(IL) -19 is a member of the recently described IL-10 family of cytokines. Based on the genomic localization of its gene, its structure, conserved amino acids, cellular sources and receptor, IL-19 forms a subfamily with IL- 20 and IL-24. The IL-19-encoding gene comprises seven exons and is located on chromosome 1. Secreted IL-19 is composed of 159 amino acids that form an α-helical structure. IL-19 is produced by activated monocytes, and to a lesser extent, by B cells. As known so far, IL-19 functions through a receptor complex composed of IL-20R1 and IL-20R2, which is also utilized by IL-20 and IL-24. High levels of both receptor chains are present in several stromal tissues including the skin, lungs, and tissues from the reproductive organs. However, no expression is found in any immune cell population. Nonetheless, all effects of IL-19 described so far concern immune cells. Such conflicting data may be due to the existence of an additional (so far undiscovered) receptor complex for IL-19, or to the ability of the known IL-19 receptor to mediate its effects when present on the cell surface at a very low density. IL-19 has been shown to enhance the production of Th2 cytokines in T cells. Furthermore, it induced IL-10 expression in monocytes. Apart from the implied role for IL-19 in atopic and allergic responses and disorders, it also seems to be involved in the pathogenesis of the Th1-type skin disease psoriasis. IL-19 therefore represents an exciting new cytokine with immunoregulatory functions.
Full-text · Article · Jul 2006 · Anti-Inflammatory & Anti-Allergy Agents in Medicinal Chemistry (Formerly Cu rrent Medicinal Chemistry - Anti-Inflammatory and Anti-Allergy Agents)
[Show abstract][Hide abstract] ABSTRACT: β-Defensins are a family of small cationic peptides involved in the innate response to microbial infection. Although their
role in microbial killing is well established, the mechanisms through which this occurs remain largely undefined. Here, using
protein array technology, we describe a role for human β-defensins in the induction of an inflammatory cytokine response by
human peripheral blood mononuclear cells (PBMCs). Human β-defensins 1, 2, and 3 were examined for induction of an array of
cytokines and chemokines. Some cytokines, such as interleukin 8 (IL-8) and monocyte chemoattractant protein 1, were up-regulated
by all three defensins, while others, such as IL-6 and IL-10, were induced more selectively. It was notable that each defensin
induced a unique pattern of cytokines. This report documents, for the first time, an analysis of the composite cytokine response
of human PBMCs to β-defensins. The induction or up-regulation of a number of cytokines involved in the adaptive immune response
suggests a possible role for these defensins in linking innate and acquired immunity.
Full-text · Article · May 2006 · Antimicrobial Agents and Chemotherapy
[Show abstract][Hide abstract] ABSTRACT: Lactoferrin is an antimicrobial protein which plays an important role in regulating bacteria that are associated with aggressive periodontitis. Lactoferrin kills directly (via its strongly cationic N-terminal region) and indirectly, through sequestering the iron that bacteria require for growth. As aggressive periodontitis has a strong heritable component, we hypothesized that genetic variation within the lactoferrin gene may play a role in susceptibility to this condition. We have identified and examined a novel, functional, single-point A/G nucleotide mutation causing a threonine/alanine substitution at position 11 (T11A) of the secreted lactoferrin protein. In a pilot case-controlled study of aggressive periodontitis, analysis of 46 African-American patients and 78 controls showed that patients were twice as likely to express the G nucleotide (alanine) allele over controls (60.3 vs 30.4%; P=0.0007, odds ratio=2.564, 95% CI=1.475-4.459). A Caucasian population of 77 patients and 131 controls showed no such association (P=0.5201, odds ratio=0.862, 95% CI=0.548-1.356). The data presented provide a new insight into the genetic susceptibility to aggressive periodontitis.
Full-text · Article · Nov 2005 · Genes and Immunity
[Show abstract][Hide abstract] ABSTRACT: IL-19 is a novel, recently identified member of the IL-10 family of cytokines. We identified IL-10 as a cytokine that was strongly induced in IL-19-stimulated PBMC. IL-19-induced IL-10 secretion was dose-dependent and could be detected in culture supernatants after 3 h of stimulation. Furthermore, quantitative RT-PCR analysis demonstrated that IL-19 stimulation increased the level of IL-10 mRNA present within cells, suggesting that IL-19 is a transcriptional activator of IL-10. IL-19 was also able to induce its own expression, with IL-10 potently down-regulating this IL-19 'auto-induction'. LPS induction of IL-19 expression was also regulated by IL-10, demonstrating that IL-10 is likely an important regulator of human IL-19 induction. Maturation of dendritic cells from human PBMC in the presence of IL-19 resulted in an increase in IL-10 levels within these cells, whereas IL-12 was not affected. These results advance our understanding of the function of this novel cytokine and its regulation within the human immune system, in addition to providing a new insight into the control of the important immunoregulatory cytokine, IL-10.
Full-text · Article · Jun 2005 · European Journal of Immunology
[Show abstract][Hide abstract] ABSTRACT: A powerful, cost-effective new method for studying single-nucleotide polymorphisms (SNPs) is described. This method is based
on the use of hairpin-shaped primers (HP), which give a sensitive and specific PCR amplification of each specific allele,
without the use of costly fluorophore-labeled probes and any post-PCR manipulation. The amplification is monitored in real-time
using SYBR Green I dye and takes only 2 h to yield results. The HP assay has a simple design and utilizes a conventional real-time
PCR apparatus. The −44 C→G transversion in the DEFB1 gene (which encodes human β-defensin 1) has been previously associated with Candida carriage in oral epithelia. In this study, we analyzed the association between early-onset periodontal disease (EOP) and
the −44 SNP. We used an HP assay to study the distribution of the −44 SNP in 264 human DNAs obtained from two cohorts of EOP
patients and healthy controls from different ethnic backgrounds. The results indicate that the −44 SNP has a similar distribution
between EOP and healthy patients, suggesting that it is not associated with the disease.
Full-text · Article · Aug 2004 · Clinical and Diagnostic Laboratory Immunology
[Show abstract][Hide abstract] ABSTRACT: Interleukin-19 (IL-19) is a newly discovered member of the IL-10 family of ligands whose function is presently undefined. We recently described its cloning and initial characterization and in so doing, noted that the induction of IL-19 by LPS in human monocytes was down-regulated by interferon-gamma (IFN-gamma) and up-regulated by IL-4. This preliminary observation led us to speculate that IL-19 may play a role in the Th1/Th2 system and we examined this hypothesis further. Our results suggested that IL-19 is able to influence the maturation of human T-cells. CD4+ T-cells resulting from SEB stimulation in the presence of IL-19 contained a higher proportion of IL-4 producing cells than those developing in the absence of IL-19. This observation was complimented by the observation that fewer IFN-gamma cells accrued in the presence of IL-19, thereby suggesting that IL-19 altered the balance of Th1/Th2 cells in favour of Th2. Furthermore, in whole PBMC cultures, IL-19 up-regulated IL-4 and down-regulated IFNgamma in a dose-dependent manner. These results are presented here in review format, in the context of an overall discussion of IL-19 and its receptor.
Full-text · Article · Jun 2004 · International Immunopharmacology