The Role of Interferon Receptors α/ß/γ Ablation During Western Diet-Induced Obesity and Insulin Resistance in the Inflectional Model AG129 Mice Strain.

Diet-induced obesity triggers elevation of circulating pro-inflammatory cytokines and acute-phase proteins, including interferons (IFNs). IFNs strongly contribute to low-grade inflammation associated with obesity-related complications, such as nonalcoholic fat liver disease and diabetes. In this study, AG129 mice model (double-knockout strain for IFN α/ß/γ receptors) was fed with a high-fat high-sucrose (HFHS) diet (Western diet) for 20 weeks aiming to understand the impact of IFN receptor ablation on diet-induced obesity, insulin resistance, and nonalcoholic fat liver disease. Mice were responsive to the diet, becoming obese after 20 weeks of HFHS diet which was accompanied by 2-fold increase of white adipose tissues. Moreover, animals developed glucose and insulin intolerance, as well as dysregulation of insulin signaling mediators such as Insulin Receptor Substrate 1 (IRS1), protein kinase B (AKT), and S6 ribosomal protein. Liver increased interstitial cells, and lipid accumulation was also found, presenting augmented fibrotic markers (transforming growth factor beta 1 [Tgfb1], Keratin 18 [Krt18], Vimentin [Vim]), yet lower expression on IFN receptor downstream proteins (Toll-like receptor [TLR] 4, nuclear factor kappa-light-chain-enhancer of activated B cells [NFκB], and cAMP response element-binding protein [CREB]). Thus, IFN receptor ablation promoted effects on NFκB and CREB pathways, with no positive effects on systemic homeostasis in diet-induced obese mice. Therefore, we conclude that IFN receptor signaling is not essential for promoting the complications of diet-induced obesity and thus cannot be correlated with metabolic diseases in a noninfectious condition.

Glioprotective effects of resveratrol in hypothalamic astrocyte cultures obtained from interferon receptor knockout (IFNα/ßR-/-) mice.

Astrocytes play essential roles in the central nervous system (CNS), such as the regulation of glutamate metabolism, antioxidant defenses, and inflammatory/immune responses. Moreover, hypothalamic astrocytes seem to be crucial in the modulation of inflammatory processes, including those related to type I interferon signaling. In this regard, the polyphenol resveratrol has emerged as an important glioprotective molecule to regulate astrocyte functions. Therefore, this study aimed to investigate the immunomodulatory and protective effects of resveratrol in hypothalamic astrocyte cultures obtained from mouse depleted of type I interferon receptors (INF-α/ß-/-), a condition that can impair immune and inflammatory functions. Resveratrol upregulated glutamate transporter and glutamine synthetase gene expression, as well as modulated the release of wide range of cytokines and genes involved in the control of inflammatory response, besides the expression of adenosine receptors, which display immunomodulatory functions. Resveratrol also increased genes associated with redox balance, mitochondrial processes, and trophic factors signaling. The putative genes associated with glioprotective effects of resveratrol, including nuclear factor erythroid derived 2 like 2 (Nrf2), heme oxygenase 1 (HO-1), sirtuin 1 (SIRT1), and phosphoinositide 3-kinase (PI3K)/Akt, were further upregulated by resveratrol. Thus, our data show that resveratrol was able to modulate key genes associated with glial functionality and inflammatory response in astrocyte cultures derived from IFNα/ßR-/- mice. These data are in agreement with previous results, reinforcing its glioprotective effects even in hypothalamic astrocytes with altered inflammatory and immune signaling. Finally, this polyphenol can prepare astrocytes to better respond to injuries, including those associated with neuroimmunology defects.

Association of TNFRSF1A and IFNLR1 Gene Polymorphisms with the Risk of Developing Breast Cancer and Clinical Pathologic Features.

Several genes have been associated with breast cancer (BC) susceptibility. The tumor necrosis factor receptor superfamily, member 1A (TNFRSF1A), and interferon lambda receptor 1 (IFNLR1) genes encode receptors that mediate the action of inflammatory cytokines. Previous studies have demonstrated the association of the variants rs1800693 (TNFRSF1A) and rs4649203 (IFNLR1) with some inflammatory diseases. The present study aimed to verify a possible association of these variants with BC, its clinical pathologic features, as well as epidemiological data in a Brazilian population. A total of 243 patients and 294 individuals without history of BC were genotyped for these polymorphisms through TaqMan® SNP genotyping assays by qPCR. For the TNFRSF1A gene, no significant results were found. For IFNLR1, the AA genotype (p = 0.008) and the A allele (p = 0.02) were significantly associated with a lower risk of developing BC. When analyzing the age, it was observed that each increase of one year contributes to the development of BC (p < 0.001). Also, the smoking habit (p < 0.001) and body mass index (p = 0.018) increase the risk of disease development. Analyzing progesterone receptor factor an association was found with the AA genotype of the IFNLR1 (p = 0.02). The findings suggest that polymorphism in the immune-related IFNLR1 gene contribute to BC susceptibility in a Brazilian population. These findings can contribute to the further understanding of the role this gene and pathways in BC development.

Interferon III-related IL28RA variant is associated with rheumatoid arthritis and systemic lupus erythematosus and specific disease sub-phenotypes.

BACKGROUND: The interferon pathways have been commonly implicated in autoimmune disease development but the identity of the genes involved has not yet been fully clarified. Variation in genes involved in interferon pathways is expected to have a role in the etiology of these diseases. METHODS: The potential association of a polymorphism in the IL28RA gene, involved in these pathways, with susceptibility to systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) and disease-related phenotypes was investigated in 603 Brazilian individuals (354 well-characterized SLE and RA patients, and 249 controls). IL28RA (rs4649203) variant was genotyped by TaqMan assay. Statistical analysis was performed including both diseases and a comprehensive list of patient clinical manifestations. RESULTS: The rs4649203-G (minor) allele was associated with SLE and RA occurrence and was shown to be a risk factor for serositis and anemia among SLE patients as well as a protective factor for rheumatoid vasculitis and rheumatoid nodules in RA patients, suggesting an association with a milder form of the disease. CONCLUSIONS: The IL28RA gene may contribute to SLE and RA susceptibility and to specific clinical manifestations of the diseases.

Functional Characterization of an Interferon Gamma Receptor-Like Protein on Entamoeba histolytica.

Entamoeba histolytica is an anaerobic parasitic protozoan and the causative agent of amoebiasis. E. histolytica expresses proteins that are structurally homologous to human proteins and uses them as virulence factors. We have previously shown that E. histolytica binds exogenous interferon gamma (IFN-γ) on its surface, and in this study, we explored whether exogenous IFN-γ could modulate parasite virulence. We identified an IFN-γ receptor-like protein on the surface of E. histolytica trophozoites by using anti-IFN-γ receptor 1 (IFN-γR1) antibody and performing immunofluorescence, Western blot, protein sequencing, and in silico analyses. Coupling of human IFN-γ to the IFN-γ receptor-like protein on live E. histolytica trophozoites significantly upregulated the expression of E. histolytica cysteine protease A1 (EhCP-A1), EhCP-A2, EhCP-A4, EhCP-A5, amebapore A (APA), cyclooxygenase 1 (Cox-1), Gal-lectin (Hgl), and peroxiredoxin (Prx) in a time-dependent fashion. IFN-γ signaling via the IFN-γ receptor-like protein enhanced E. histolytica's erythrophagocytosis of human red blood cells, which was abrogated by the STAT1 inhibitor fludarabine. Exogenous IFN-γ enhanced chemotaxis of E. histolytica, its killing of Caco-2 colonic and Hep G2 liver cells, and amebic liver abscess formation in hamsters. These results demonstrate that E. histolytica expresses a surface IFN-γ receptor-like protein that is functional and may play a role in disease pathogenesis and/or immune evasion.

Gene expression in chronic granulomatous disease and interferon-γ receptor-deficient cells treated in vitro with interferon-γ.

Interferon-γ (IFN-γ) plays an important role in innate and adaptive immunity against intracellular infections and is used clinically for the prevention and control of infections in chronic granulomatous disease (CGD) and inborn defects in the IFN-γ/interleukin (IL)-12 axis. Using transcriptome profiling (RNA-seq), we sought to identify differentially expressed genes, transcripts and exons in Epstein-Barr virus-transformed B lymphocytes (B-EBV) cells from CGD patients, IFN-γ receptor deficiency patients, and normal controls, treated in vitro with IFN-γ for 48 hours. Our results show that IFN-γ increased the expression of a diverse array of genes related to different cellular programs. In cells from normal controls and CGD patients, IFN-γ-induced expression of genes relevant to oxidative killing, nitric oxide synthase pathway, proteasome-mediated degradation, antigen presentation, chemoattraction, and cell adhesion. IFN-γ also upregulated genes involved in diverse stages of messenger RNA (mRNA) processing including pre-mRNA splicing, as well as others implicated in the folding, transport, and assembly of proteins. In particular, differential exon expression of WARS (encoding tryptophanyl-transfer RNA synthetase, which has an essential function in protein synthesis) induced by IFN-γ in normal and CGD cells suggests that this gene may have an important contribution to the benefits of IFN-γ treatment for CGD. Upregulation of mRNA and protein processing related genes in CGD and IFNRD cells could mediate some of the effects of IFN-γ treatment. These data support the concept that IFN-γ treatment may contribute to increased immune responses against pathogens through regulation of genes important for mRNA and protein processing.

IFN-γR2 is strongly expressed on endothelial cells of gingival tissues from patients with chronic periodontitis.

OBJECTIVE: Chronic periodontitis (CP) is characterized by gingival inflammation and bone destruction. It has been reported that interferon-gamma (IFN-γ) levels are high in CP patients; however, the IFN-γ receptor (IFN-γR) has not been studied in gingival tissue from these patients. To evaluate IFN-γ levels and IFN-γR expression in gingival tissue biopsies from chronic periodontitis patients compared with healthy subjects (HS). MATERIAL AND METHODS: Gingival tissues were obtained from all study subjects, CP (n = 18) and healthy subjects (HS) (n = 12). A tissue section of each study subject was embedded in paraffin blocks to determine the expression of IFN-γ R (IFN-γR1 and IFN-γR2) through immunohistochemistry. Another section of the tissue was homogenized and IFN-γ was measured by the ELISA technique. RESULTS: No significant differences were found in the IFN-γR1 expression within the cell layers of the gingival tissue of the study groups. When analyzing the IFN-γR2 expression it was found that IFN-γR2 is strongly expressed in the endothelial cells of CP patients when compared to HS (p<0.05). IFN-γ concentrations in the gingival tissue were significantly higher in CP patients than in HS. No significant correlation between IFN-γ levels and the expression of IFN-γR1 and IFN-γR2 was found. However, a positive correlation between IFN-γ levels and clinical parameters [probing depth (PD) and clinical attachment level (CAL)] was found. CONCLUSION: The study of IFN-γR expression in gingival tissue samples from patients with CP showed an increase only in the IFN-γR2 chain in endothelial cells when compared to HS.

IFN-γR2 is strongly expressed on endothelial cells of gingival tissues from patients with chronic periodontitis

Abstract Chronic periodontitis (CP) is characterized by gingival inflammation and bone destruction. It has been reported that interferon-gamma (IFN-γ) levels are high in CP patients; however, the IFN-γ receptor (IFN-γR) has not been studied in gingival tissue from these patients. Objective: To evaluate IFN-γ levels and IFN-γR expression in gingival tissue biopsies from chronic periodontitis patients compared with healthy subjects (HS). Material and Methods: Gingival tissues were obtained from all study subjects, CP (n = 18) and healthy subjects (HS) (n = 12). A tissue section of each study subject was embedded in paraffin blocks to determine the expression of IFN-γ R (IFN-γR1 and IFN-γR2) through immunohistochemistry. Another section of the tissue was homogenized and IFN-γ was measured by the ELISA technique. Results: No significant differences were found in the IFN-γR1 expression within the cell layers of the gingival tissue of the study groups. When analyzing the IFN-γR2 expression it was found that IFN-γR2 is strongly expressed in the endothelial cells of CP patients when compared to HS (p<0.05). IFN-γ concentrations in the gingival tissue were significantly higher in CP patients than in HS. No significant correlation between IFN-γ levels and the expression of IFN-γR1 and IFN-γR2 was found. However, a positive correlation between IFN-γ levels and clinical parameters [probing depth (PD) and clinical attachment level (CAL)] was found. Conclusion: The study of IFN-γR expression in gingival tissue samples from patients with CP showed an increase only in the IFN-γR2 chain in endothelial cells when compared to HS.

[Disseminated infection by M. tuberculosis complex in patient with IFN-γ receptor 1 complete deficiency]. / Infección diseminada por complejo M. tuberculosis en paciente con deficiencia completa del receptor 1 de interferón-γ.

BACKGROUND: Several mutations have been described leading to impaired immunity in the IL-12/IFN-γ axis and, they confer susceptibility to mycobacterial infections. One of the more serious clinical phenotypes is secondary to mutations at IFN-γ receptor 1 gene, characterized by an early onset and more severe disease. CLINICAL REPORT: We present a 3-month-old female patient with systemic M. tuberculosis complex who has a homozygous mutation, it affects the splicing site at IFNGR1 c.201-1G> T. At time of this report, she is with antimycobacterial treatment in the protocol of pluripotent hematopoietic cell transplantation (TCHP). CONCLUSION: It has been reported that antiphimic treatment should be maintained until the immune system is restored by the TCHP. If patients receive THCP before the age of 1 year old, they have a better prognosis. Diminish the levels of IFN-γ in plasma before the procedure is associated to better results.

Antecedentes: Se han descrito diversas mutaciones que llevan a inmunidad alterada en el eje interleucina 12/interferón gamma (IL-12/IFN-γ) y confieren susceptibilidad a infecciones por micobacterias. Uno de los fenotipos clínicos más graves es secundario a mutaciones en el gen del receptor 1 de IFN-γ, caracterizado por su inicio a temprana edad y mayor gravedad. Caso clínico: Paciente femenina de 3 meses de edad, con afección sistémica por complejo M. tuberculosis, en quien se identificó una mutación homocigota que afecta el sitio de splicing a nivel de IFNGR1 c.201-1G>T. Al momento de este reporte es manejada con antifímicos en un protocolo de trasplante de células hematopoyéticas pluripotenciales. Conclusión: Se ha informado que el tratamiento antifímico debe mantenerse hasta que se restaure el sistema inmunológico mediante trasplante de células hematopoyéticas pluripotenciales, cuyo mejor pronóstico se asocia con edad del receptor menor a un año y reducción de los niveles plasmáticos de IFN-γ.

White adipose tissue IFN-γ expression and signalling along the progression of rodent cancer cachexia.

Cachexia is associated with increased morbidity and mortality in cancer. The White adipose tissue (WAT) synthesizes and releases several pro-inflammatory cytokines that play a role in cancer cachexia-related systemic inflammation. IFN-γ is a pleiotropic cytokine that regulates several immune and metabolic functions. To assess whether IFN-γ signalling in different WAT pads is modified along cancer-cachexia progression, we evaluated IFN-γ receptors expression (IFNGR1 and IFNGR2) and IFN-γ protein expression in a rodent model of cachexia (7, 10, and 14days after tumour implantation). IFN-γ protein expression was heterogeneously modulated in WAT, with increases in the mesenteric pad and decreased levels in the retroperitoneal depot along cachexia progression. Ifngr1 was up-regulated 7days after tumour cell injection in mesenteric and epididymal WAT, but the retroperitoneal depot showed reduced Ifngr1 gene expression. Ifngr2 gene expression was increased 7 and 14days after tumour inoculation in mesenteric WAT. The results provide evidence that changes in IFN-γ expression and signalling may be perceived at stages preceding refractory cachexia, and therefore, might be employed as a means to assess the early stage of the syndrome.

Altered immune parameters correlate with infection-related hospitalizations in children with Down syndrome.

In addition to previously studied immunological variables, the relative expression of IFNGR2, IFNAR1, CD18, and CD275 (all encoded in chromosome 21) on circulating leucocytes and multifunctional T cells (evaluated by an intracellular cytokine/proliferation assay) were compared between children with Down syndrome (DS) and healthy controls (HC). As previously reported, numbers of lymphocytes, CD4(+) T cells, Treg cells, B cells, and levels of serum IgM were decreased, and levels of IgG and IgA were increased in children with DS. Moreover, the relative expression of CD18 on T and B cells (previously and not previously reported, respectively) were elevated in DS children (p⩽0.01). Age and numbers of B and Treg cells moderately correlated with retrospectively identified infection related hospitalizations (rho: 0.300-0.460, p⩽0.003). Age and the numbers of Treg cells also correlated with prospectively identified infection related hospitalizations. Future studies are necessary to clarify the role of these parameters in the immunity of DS patients.

Association of polymorphism within the interleukin-28 receptor alpha gene, but not in interleukin-28B, with lower urinary tract symptoms (LUTS) in Chinese.

The aim of this study was to determine the relationship between polymorphisms in the IL-28B and IL-28R genes and lower urinary tract symptoms (LUTS) in Chinese patients. Genomic DNA was extracted from 553 whole blood samples from 233 patients with LUTS resulted from benign prostatic hyperplasia and 320 control subjects. The IL-28B rs12979860 and rs8099917, and IL-28Rα rs10903035 and rs11249006 polymorphisms were genotyped using a polymerase chain reaction-restriction fragment length polymorphism assay. For rs10903035, the frequencies of the "G" allele and the "AG/GG" genotypes in the LUTS group were significantly lower than those in the control group ("G" vs "A": OR = 0.655, 95%CI = 0.506-0.849; AG/GG vs "AA": OR = 0.538, 95%CI = 0.379-0.764, respectively). Combined effects analysis of rs12979860 and rs10903035 showed that the "CC+AG/GG" and "CT+AA" genotypes were significantly less frequent in the LUTS group ("CC+AG/GG" vs "CC+AA": OR = 0.553, 95%CI = 0.381-0.801; "CT+AG/GG" vs "CC+AA": OR = 0.429, 95%CI = 0.198- 0.927, respectively). In addition, the combined effects of the rs8099917 and rs10903035 "TT+AG/GG" and "GT+AG/GG" genotypes were also significantly lower in the LUTS group ("TT+AG/GG" vs "TT+AA": OR = 0.569, 95%CI = 0.395-0.821; "GT+AG/GG" vs "TT+AA": OR = 0.318, 95%CI = 0.128-0.788, respectively). Stratification analysis revealed that the frequencies of the rs11249006 "AG/GG" genotypes in the subgroups of size ≤4.11 and IPSS ≤ 28 were significantly higher than those in the subgroups of size >4.11 and IPSS > 28. Therefore, the IL-28Rαgene polymorphism might be involved in the development of LUTS.

Relationship between UV-irradiated HaCaT cell cytokines and Th1/Th2 imbalance.

We have previously found that an imbalance of Tc1/Tc2 T cell subtypes in vivo impacts the development of photodermatitis. The aim of this study was to investigate the relationship between cytokines derived from keratinocytes exposure to UV and the imbalance of Th subgroups. We used different doses of UVA and UVB to irradiate HaCaT cells. Twelve hours after irradiation, the expression of IL-10R, IL-4R, IL-12R, and IFN-γR proteins was observed using the S-P method, and the percentage of positive cells calculated. Protein levels of the respective ligands in the supernatant was measured by ELISA. Our results showed low levels of expression of the interrogated proteins in unirradiated HaCaT cells, and little or no expression could be detected in the supernatant. Little or no expression was also observed for IL-12R and IFN-γR 12 h after UVA or UVB irradiation. However, the expression of IL-10R and IL-10 was upregulated 12 h following UVB irradiation, as well as following lower dose UVA irradiation. In contrast, higher dose UVA decreased the expression of IL-10R and IL-10. The expression of IL-4R was increased following high doses of UVA and UVB irradiation, whereas no expression was observed after lower dose UV exposure. There was no change in IL-4 secretion into the supernatant. Our results demonstrate that the effects of UV exposure on keratinocyte-derived cytokines are different according to the doses of irradiation and the types of cytokines, and suggest that keratinocyte-derived cytokines after UV exposure might cause an imbalance of Th1/Th2.

Taenia crassiceps infection and its excreted/secreted products inhibit STAT1 activation in response to IFN-γ.

It is well understood that helminth infections modulate the immune responses of their hosts but the mechanisms involved in this modulation are not fully known. Macrophages and dendritic cells appear to be consistently affected during this type of infection and are common target cells for helminth-derived molecules. In this report, we show that macrophages obtained from chronically Taenia crassiceps-infected mice displayed an impaired response to recombinant murine IFN-γ, but not to recombinant murine IL-4, as measured based on the phosphorylation of STAT1 and STAT6, respectively. These macrophages expressed high levels of SOCS3. However, the inhibition of phosphatase activity by orthovanadate restored the IFN-γ response of these macrophages by increasing STAT1 phosphorylation without affecting SOCS3 expression. Therefore, we aimed to identify the phosphatases associated with IFN-γ signaling inhibition and found that macrophages from T. crassiceps-infected mice displayed enhanced SHP-1 expression. Interestingly, the exposure of naïve macrophages to T. crassiceps excreted/secreted products similarly interfered with IFN-γ-induced STAT1 phosphorylation. Moreover, macrophages exposed to T. crassiceps excreted/secreted products expressed high levels of SOCS3 as well as SHP-1. Strikingly, human peripheral blood mononuclear cells that were exposed to T. crassiceps excreted/secreted products in vitro also displayed impaired STAT1 phosphorylation in response to IFN-γ; again, phosphatase inhibition abrogated the T. crassiceps excreted/secreted product-altered IFN-γ signaling. These data demonstrate a new mechanism by which helminth infection and the products derived during this infection target intracellular pathways to block the response to inflammatory cytokines such as IFN-γ in both murine and human cells.

Association of genetic variants of membrane receptors related to recognition and induction of immune response with Helicobacter pylori infection in Ecuadorian individuals.

Helicobacter pylori (Hp) has a worldwide distribution showing its higher prevalence of infection in developing countries. Toll-like receptors (TLRs) and C-type lectin receptors (CLRs) are proteins that recognize pathogen-associated molecular patterns (PAMPs) and initiate an innate immune response by promoting growth and differentiation of specialized hematopoietic cells for host defense. Gastric infections led by Hp induce a Th-1 cellular immune response, regulated mainly by the expression of IFN-γ. In this retrospective case-control study, we evaluated the TLR1 1805T/G, TLR2 2029C/T, TLR4 896A/G, CD209 -336A/G and IFNGR1 -56C/T polymorphisms and their relationship with susceptibility to Hp infection. TLR1 1805T/G showed statistical differences when the control (Hp-) and infected (Hp+) groups (P = 0.041*) were compared; the TLR1 1805G allele had a protective effect towards infection (OR = 0.1; 95% CI = 0.01-0.88, P = 0.033*). Similarly, the IFNGR1 -56C/T polymorphism showed statistical differences between Hp+ and Hp- (P = 0.018*), and the IFNGR1 -56TT genotype exhibited significant risk to Hp infection (OR = 2.9, 95% CI = 1.27-6.54, P = 0.018*). In conclusion, the pro-inflammatory TLR1 1805T and IFNGR1 -56T alleles are related with susceptibility to Hp infection in Ecuadorian individuals. The presence of these polymorphisms in individuals with chronic infection increases the risk of cellular damage and diminishes the cellular immune response efficiency towards colonizing agents.

Association study of SNPs of genes IFNGR1 (rs137854905), GSTT1 (rs71748309), and GSTP1 (rs1695) in gastric cancer development in samples of patient in the northern and northeastern Brazil.

Cancer is a multifactorial disease with a high mortality rate in Brazil and worldwide. Gastric cancer (GC) is considered the fourth type of malignancy more frequent in the population worldwide and the second leading cause of death. This work aimed to evaluate single nucleotide polymorphisms (SNPs) of IFNGR1, GSTT1, and GSTP1 genes samples in gastric cancer. We analyzed 60 samples of gastric cancer, 26 diffuse and 34 intestinal types, totaling 120 alleles for each SNP. The results were obtained by PCR and allele-specific PCR. Statistical analyzes performed using BioEstat 5.0 software, applying the Fisher's exact test and chi-square. Only the SNP gene GSTP1 (rs1695) were significantly associated with gastric cancer in the samples analyzed (χ(2) = 8.73, P < 0.05). Our results suggest that the GSTP1 gene SNP (rs1695) can be considered a risk factor associated with gastric carcinogenesis.

Immunogenicity and protection conferred by Mycobacterium habana in a murine model of pulmonary tuberculosis.

Mycobacterium habana was isolated in Cuba in 1971. Later, was demonstrated its protection capacity in mycobacterial infection. Here we determined the level of virulence, immunogenicity and the efficacy of three different M. habana strains as attenuated live vaccines. Intratracheal infection of BALB/c mice with high dose M. habana TMC 5135 or IPK-337 strains permitted 100% survival and limited tissue damage. Mice infected with M. habana IPK-220 showed lower attenuation, so it was discarded for the vaccination experiments. Strains IPK-337 and TMC 5135 were used as subcutaneous vaccine and compared with BCG. Nude mice vaccinated with strain 5135 showed longer but non-significant survival than BCG vaccinated animals. Cell suspensions from M. habana vaccinated mice produced higher IFNγ after stimulation with mycobacterial antigens than BCG recipients. After four months of challenge with Mycobacterium tuberculosis strain H37Rv, mice vaccinated with BCG substrain Phipps or strain TMC 5135 showed total survival, while 60% survival was exhibited by animals vaccinated with M. habana IPK-337. Both M. habana strains do not prevent the infection with M. tuberculosis but avoided the progression of the experimental disease; strain TMC 5135 showed similar level of protection than BCG.

Expression of interferon-γ, interferon-α and related genes in individuals with Down syndrome and periodontitis.

BACKGROUND: Recently, attenuation of anti-inflammatory and increase of pro-inflammatory mediators was demonstrated in individuals with Down syndrome (DS) in comparison with euploid patients during periodontal disease (PD), suggesting a shift to a more aggressive inflammation in DS. AIM: To determine the influence of DS in the modulation of interferons (IFNs) signaling pathway in PD. MATERIALS AND METHODS: Clinical periodontal assessment was performed and gingival tissue samples obtained from a total of 51 subjects, including 19 DS individuals with PD, 20 euploid individuals with PD and 12 euploid individuals without PD. Expression levels of interferon-gamma (IFNG) and interferon-alpha (IFNA), and their receptors IFNGR1, IFNGR2, IFNAR1 and IFNAR2, the signaling intermediates Janus kinase 1 (JAK1), signal transducer and activator of transcription 1 (STAT1) and interferon regulatory factor 1 (IRF1) were determined using real time quantitative polymerase chain reaction (qPCR). RESULTS: Clinical signs of periodontal disease were markedly more severe in DS and euploid patients with PD in comparison to euploid and periodontally healthy patients. There was no difference on mRNA levels of IFNA, IFNG, INFGR2, IFNAR1 and IFNAR2 between DS and euploid individuals, even though some of these genes are located on chromosome 21. STAT1 and IRF1 mRNA levels were significantly lower in DS patients in comparison with euploid individuals with PD. In euploid individuals, PD was associated with an increased expression of IFNGR1, IFNGR2, IFNAR1, STAT1 and IRF1. CONCLUSIONS: Reduced expression of STAT1 and IRF1 genes indicate an impaired activation of IFNs signaling in individuals with DS and PD. Expression of IFNA, IFNG and IFN receptors was not altered in DS patients, indicating that indirect mechanisms are involved in the reduced activation of IFN signaling.

A novel internalization motif regulates human IFN-γ R1 endocytosis.

This study tested the hypothesis that the IFN-γ R1 287-YVSLI-91 intracellular motif regulates its endocytosis. IFN-γ exerts its biological activities by interacting with a specific cell-surface RC composed of two IFN-γ R1 and two IFN-γ R2 chains. Following IFN-γ binding and along with the initiation of signal transduction, the ligand and IFN-γ R1 are internalized. Two major types of consensus-sorting signals are described in receptors, which are rapidly internalized from the plasma membrane to intracellular compartments: tyrosine-based and dileucine-based internalization motifs. Transfection of HEK 293 cells and IFN-γ R1-deficient fibroblasts with WT and site-directed, mutagenesis-generated mutant IFN-γ R1 expression vectors helped us to identify region IFN-γ R1 287-YVSLI-291 as the critical domain required for IFN-γ-induced IFN-γ R1 internalization and Y287 and LI290-291 as part of a common structure essential for receptor endocytosis and function. This new endocytosis motif, YxxLI, shares characteristics of tyrosine-based and dileucine-based internalization motifs and is highly conserved in IFN-γ Rs across species. The IFN-γ R1 270-LI-271 dileucine motif, previously thought to be involved in this receptor endocytosis, showed to be unnecessary for receptor endocytosis.