Analysis by in situ hybridization of cells expressing mRNA for tumor-necrosis factor in the developing thymus of mice.

We have used in situ hybridization to investigate the expression of TNF-alpha genes by thymic cells during fetal development in mice. In 14-day-old fetal thymuses, very scarce cells produce TNF-alpha mRNA. A second phase of cytokine gene expression starts on day 16. The density of positive cells progressively increases up to day 20. Thymuses at 15 days of gestation and after birth do not express detectable cytokine mRNA. In an attempt to identify the nature of the TNF-alpha mRNA-producing cells, acid phosphatase activity, which is characteristic of the macrophage lineage, was studied in the same thymuses. Acid phosphatase-positive cells only appear on day 15. Their frequency increases up to birth. However, no correlation can be established between acid phosphatase--and TNF alpha mRNA--positive cells. The results indicate that a small subset of thymic cells is responsible for TNF-alpha mRNA production during ontogeny: These cells are not yet identified. The possible role of TNF-alpha in thymic ontogeny is discussed.     

Inflammatory conditions distinctively alter immunological functions of Langerhans-like cells and dendritic cells in vitro

The specific function of human skin-resident dendritic cell (DC) subsets in the regulation of immunity or tolerance is still a matter of debate. Langerhans cells (LC) induce anti-viral immune responses but, conversely to dermal DC, maintain tolerance to bacteria. However, the definite function of epidermal LC and cutaneous DC appears even more complex under inflammatory conditions. Here we investigated the immune responses of human immature monocyte-derived DC (MoDC) and LC-like cells (MoLC) upon stimulation with different Toll-like receptor ligands in the presence or absence of pro-inflammatory cytokines tumour necrosis factor-α (TNF-α) and interleukin-1β (IL-1β). In MoDC, bacterial antigens selectively up-regulated CD83 and CD86 expression and induced the release of T helper type 1 (Th1) and Th17 cytokines and led to a higher CCR7-dependent migratory capacity compared with a low responsiveness of MoLC. Importantly, MoLC activation with lipopolysaccharide under inflammatory conditions strongly enhanced a phenotypically mature state, increased IL-12p70, IL-23 and IL-6 production and Th1 cytokine secretion by CD4⁺ T cells. Treatment with poly(I:C) specifically up-regulated surface expression of co-stimulatory molecules and increased release of IL-12p70 in MoLC and co-stimulation with TNF-α and IL-1β further elevated Th1 and Th17 cytokine production. Poly(I:C)-induced up-regulation of type I interferon mRNA levels in MoLC and MoDC was Toll-like receptor 3-dependent but not, or only weakly, modulated by pro-inflammatory cytokines. Our results indicate that inflammatory conditions greatly facilitate recognition of bacteria by MoLC. Furthermore, we suggest a critical involvement of both subsets in innate defence against viruses, whereas inflammatory skin environments additionally favour MoLC as potent inducers of Th1 and Th17 cytokines.     

Expression of The αβ T-Cell Receptor Is Necessary for The Generation of The Thymic Medulla

The architecture of the thymus of mice that congenitally fail to express the αβ T-cell receptor (TCRαβ) has been examined by immunohistology. In these mice, a defined mutation was introduced into the TCRc gene by homologous recombination. By using antibodies specific for cortical or medullary epithelium and for major histocompatibility complex antigens, the network of cortical epithelium in these mice was shown to be essentially unaltered in comparison with that of normal mice. In contrast, the thymic medulla was considerably reduced in size. This analysis shows that expression of the αβ TCR but not the γδ TCR is obligatory for establishing the thymic medulla and suggests that the growth of medullary epithelial cells may require contact with TCRαβ-expressing cells.     

Developmental and Anatomical Patterns Of IL-2 Gene Expression in Vivo in The Murine Thymus

Interleukin-2 (IL-2) is a potent growth factor that mature T lymphocytes synthesize and use as a proliferation signal. Much controversy has arisen concerning whether it is used to drive the extensive proliferation of immature pre-T cells in the thymus. Immature thymocytes acquire the competence to express IL-2 at an early stage, but it has remained uncertain whether they are activated to exercise this competence in vivo. Therefore, we have used in situ hybridization and immunohistochemistry on serial sections obtained from fetal and adult thymuses of normal C57BL/6 mice and of mice bearing the scid defect to determine where, when, and whether IL-2 is expressed in vivo. Our results show a striking spatial and temporal pattern of IL-2 expression in the normal fetal thymus. We detected a burst of IL-2 mRNA accumulation at day 14.5 of gestation, which rapidly decreased by day 15. At day 15, we observed maximal IL-2 protein production that subsequently decreased by day 16 of gestation. Both in situ hybridization and immunohistochemical staining revealed an unexpectedly strict localization of IL-2 expressing cells to patches around the periphery of the fetal thymus, creating a previously unrecognized compartment of high IL-2 protein content. IL-2 production in the day-15 fetal thymus appeared to be unaffected by the scid mutation, indicating that this response is likely to be T-cell receptor (TcR)-independent. Several features distinguish the IL-2 induction pattern in the adult thymus from that in the fetal thymus. In the normal adult thymus, IL-2-expressing cells are extremely rare (found at a frequency of 10^-7), but they are reproducibly detectable as isolated cells in the outer cortex and subcapsular region of the thymus. Unlike the fetal thymic IL-2 producers, the IL-2 producers in the adult thymus are completely eliminated in mice homozygous for the scid mutation. This suggests that the IL-2-expressing cells in the normal adult thymus are of a more mature phenotype than the immature, TcR-negative cells that accumulate in the scid adult thymus. Thus, our work demonstrates that two developmentally distinct types of cell interactions induce IL-2 expression in vivo: one, a broadly localized interaction in day 14‑15 fetal thymus that is unaffected by the scid mutation; the other, a rare event that occurs asynchronously from late fetal through adult life, but which is completely eliminated by the scid defect. These results imply that significant differences exist between the physiological processing of thymocytes in the fetal and postnatal thymic microenvironments.     

A non-protective T helper 1 response against the intra-macrophage protozoan Theileria annulata

Theileria annulata is a protozoan parasite which infects and transforms bovine macrophages. Infected macrophages possess augmented antigen presentation capabilities, as they are able to activate the majority of T cells from unexposed animals. In vivo, T cells in the draining lymph node (principal site of parasite development) are activated ‘non-specifically’ by the parasite. This event is followed by failure of the immune response to control the infection. Protective immune responses against intra-macrophage protozoa are usually mediated by T helper 1 (Th1) T cell responses. Here we examine the cytokine responses made by T. annulata-activated T cells. We show that the outcome of in vitro activation of T cells by parasitized macrophages is a skewing of their cytokine responses towards preferential expression of interferon-gamma (IFN-γ) mRNA. The in vitro response is mirrored during in vivo infection, as greatly elevated amounts of IFN-γ protein are found in lymph efferent from infected lymph nodes, while expression of IL-4 mRNA within the node stops. IFN-γ production does not correlate with protection against the parasite, as infected cells flourish during peak IFN-γ production, and only very small amounts of IFN-γ are produced during the effective immune response of an immunized animal. Overproduction of IFN-γ and loss of IL-4 expression are also likely to account for the failure of B cells to reach the light zone of germinal centres, a developmental step which is tightly regulated by cytokines.     

An analysis of apoptosis in lymphoid organs and lupus disease in murine systemic lupus erythematosus (SLE)

Apoptosis is a programmed cell death process that helps to regulate both T cell and B cell development. In this study, we have investigated the levels of apoptotic death in cells of the thymuses and spleens (white matter) of autoimmune MRL-lpr/lpr mice with progressive lymphadenopathy and SLE disease activity; we also examined the renal pathology in these animals. Fas is a cell surface receptor, which when activated initiates the sequence of events that lead to apoptosis. In MRL-lpr/lpr mice Fas is defective, so the competency for apoptosis may be reduced. In young animals of advancing age the thymuses enlarged until in 5-month-old females the average weight was three times that at 1 month, and spleen and kidney weights also increased in size disproportionately. At light microscope level apoptotic cells in tissue sections were counted using both routine eosin and haematoxylin staining (to identify them by their morphology) and in situ end-labelling of cells with DNA strand breaks; their presence was further confirmed by electron microscopy. As the mice aged, the numbers of apoptotic cells in thymic cortex, thymic medulla and spleen white pulp areas reduced significantly (P < 0·01–0·001), whereas in BALB/c normal controls they increased significantly (P < 0·05). These changes were coincident with the development of severe lupus, whose activity was assessed by measuring serum anti-ssDNA and anti-dsDNA antibody titres and urinary protein (albumin) level which were elevated significantly by 5 months of age (P < 0·001 for both ssDNA and dsDNA and P < 0·01 for urine albumin) compared with their younger counterparts. Thus, lymphoid organ enlargement, decrease in apoptotic indices, elevated serum anti-ssDNA and anti-dsDNA antibody levels, and impaired renal function coincided with the onset and severity of lupus disease in lpr mice. It seems likely that there is a causal relationship between defective deletion of autoreactive lymphoid cells, imperfect Fas-mediated apoptosis and development of murine SLE.     

Changes in Laminin Chain Expression in Pre- and Postnatal Rat Pituitary Gland

Cell–matrix interaction is required for tissue development. Laminin, a major constituent of the basement membrane, is important for structural support and as a ligand in tissue development. Laminin has 19 isoforms, which are determined by combinational assembly of five α, three β, and three γ chains (eg, laminin 121 is α1, β2, and γ1). However, no report has identified the laminin isoforms expressed during pituitary development. We used in situ hybridization to investigate all laminin chains expressed during rat anterior pituitary development. The α5 chain was expressed during early pituitary development (embryonic day 12.5–15.5). Expression of α1 and α4 chains was noted in vasculature cells at embryonic day 19.5, but later diminished. The α1 chain was re-expressed in parenchymal cells of anterior lobe from postnatal day 10 (P10), while the α4 chain was present in vasculature cells from P30. The α2 and α3 chains were transiently expressed in vasculature cells and anterior lobe, respectively, only at P30. Widespread distribution of β and γ chains was also observed during development. These findings suggest that numerous laminin isoforms are involved in anterior pituitary gland development and that alteration of the expression pattern is required for proper development of the gland.     

Proliferation of distinct human T cell subsets in response to live, killed or soluble extracts of Mycobacterium tuberculosisand Myco. avium

The proliferative responses of distinct cell subsets from healthy, bacille Calmette–Guérin (BCG)-vaccinated blood donors were assessed after in vitro stimulation with live or UV-killed Mycobacterium tuberculosis and Myco. avium or with soluble extracts obtained from either mycobacterial species. Proliferation of cell subsets was evaluated by flow cytometric determination of 5-bromo-2′-deoxy-uridine incorporation into DNA and simultaneous identification of surface phenotypic markers. In the presence of monocytes, the response to whole (live or killed) bacteria was characterized by a predominant proliferation of CD4⁺ αβ⁺ T cells and, to a lesser extent, of CD8⁺ αβ⁺ T cells. Proliferation of CD8⁺ αβ⁺ T cells was primarily elicited by live rather than killed bacilli (P < 0.05). Conversely, when soluble bacterial extracts were used as stimulators, a preferential proliferation of γδ⁺ T cells, expressing predominantly Vγ9⁺ and Vδ2⁺ T cell receptor chains, was recorded. Moreover, when monocyte-depleted cell populations were directly cultured with live bacteria, a marked proportion of CD3⁻CD16⁺ (natural killer (NK)) cells was detected among the responding cells. Although both αβ, γδ and NK cells have been previously shown to react with mycobacteria in vitro, their relative contributions to the response have been difficult to assess. Using a flow cytometric technique which allows direct identification of proliferating cells within complex cell populations, our study demonstrates significant differences in the ability of various mycobacterial antigen preparations to elicit proliferation of distinct cell subsets.     

Association of CD14 and TLR4 with LPS-stimulated human normal skin fibroblasts in immunophenotype changes and secretion of TGF-β1 and IFN-γ

Objectives: We attempted to explore the association of CD14 and TLR4 with LPS-stimulated human normal skin fibroblasts in immunophenotype changes and secretion of TGF-β1 and IFN-γ, and to expand the current knowledge of the mechanisms that underlie LPS-induced scar formation. Methods: We randomized the human normal skin fibroblasts cultured in vitro into four groups. The expression profile of immune phenotypes was determined by immunohistochemical staining. Ultrastructure of cells was observed by use of transmission electron microscopy. Secretion status of TGF-β1 and IFN-γ was inspected using ELISA assay. Results: Compared with group A, the expressions of α-SMA and α1 (I) procollagen in groups B, C, D were lower, and it in group D were the lowest in all groups. The cells in group A were diversification under the electron microscope, and the ratio of the nuclear to plasma of the fibroblasts was large, with unregular nuclear membrane, more Golgi apparatus, rough endoplasmic reticulum, and microfilament and canaliculus appeared. The ultrastructure of the fibroblasts in group B, C, D was spindle and the nuclear was large, with regular nuclear membrane, more Golgi apparatus, rough endoplasmic reticulum. ELISA assay indicated that the secretion of TGF-β1 markedly lowered in groups B, C, D in comparison to group A, with the most marked decline observed in group D. Interestingly, we found significantly increased IFN-γ secretion in groups B, C, D (P < 0.05), with the latter group showing the most notable increase (P < 0.01). Conclusion: These data suggest that both combined and isolated use of CD14 and TLR4 significantly reduce α-SMA expression levels, the number of α1 (I) pro-collagen positive cells, and TGF-β secretion, while substantially increased IFN-γ secretion. The reduction and increase are especially notable when pretreating with CD14 and TLR4 combined. Here we thus draw a conclusion that both CD14 and TLR4 are associated with the immunophenotype changes and secretion of TGF-β1 and IFN-γ in LPS-stimulated human normal skin fibroblasts.     

Dual Roles of Gastric Gland Mucin-specific O-glycans in Prevention of Gastric Cancer

Gastric gland mucin is secreted from gland mucous cells, including pyloric gland cells and mucous neck cells located in the lower layer of the gastric mucosa. These mucins typically contain O-glycans carrying terminal α1,4-linked N-acetylglucosamine residues (αGlcNAc) attached to the scaffold protein MUC6, and biosynthesis of the O-glycans is catalyzed by the glycosyltransferase, α1,4-N-acetylglucosaminyltransferase (α4GnT). We previously used expression cloning to isolate cDNA encoding α4GnT, and then demonstrated that αGlcNAc functions as natural antibiotic against Helicobacter pylori, a microbe causing various gastric diseases including gastric cancer. More recently, it was shown that αGlcNAc serves as a tumor suppressor for differentiated-type adenocarcinoma. This review summarizes these findings and identifies dual roles for αGlcNAc in gastric cancer.     

c-Jun N-terminal kinase and Akt signalling pathways regulating tumour necrosis factor-α-induced interleukin-32 expression in human lung fibroblasts: implications in airway inflammation

Airway inflammatory diseases such as chronic obstructive pulmonary disease (COPD) and asthma are associated with elevated expression of interleukin-32 (IL-32), a recently described cytokine that appears to play a critical role in inflammation. However, so far, the regulation of pulmonary IL-32 production has not been fully established. We examined the expression of IL-32 by tumour necrosis factor-α (TNF-α) in primary human lung fibroblasts. Human lung fibroblasts were cultured in the presence or absence of TNF-α and/or other cytokines/Toll-like receptor (TLR) ligands or various signalling molecule inhibitors to analyse the expression of IL-32 by quantitative RT-PCR and ELISA. Next, activation of Akt and c-Jun N-terminal kinase (JNK) signalling pathways was investigated by Western blot. Interleukin-32 mRNA of four spliced isoforms (α,β,γ and δ) was up-regulated upon TNF-α stimulation, which was associated with a significant IL-32 protein release from TNF-α-activated human lung fibroblasts. The combination of interferon-γ and TNF-α induced enhanced IL-32 release in human lung fibroblasts, whereas IL-4, IL-17A, IL-27 and TLR ligands did not alter IL-32 release in human lung fibroblasts either alone, or in combination with TNF-α. Furthermore, the activation of Akt and JNK pathways regulated TNF-α-induced IL-32 expression in human lung fibroblasts, and inhibition of the Akt and JNK pathways was able to suppress the increased release of IL-32 to nearly the basal level. These data suggest that TNF-α may be involved in airway inflammation via the induction of IL-32 by activating Akt and JNK signalling pathways. Therefore, the TNF-α/IL-32 axis may be a potential therapeutic target for airway inflammatory diseases.     

Lymphocyte activation and subset redistribution in the peripheral blood in acute malaria illness: distinct γδ+ T cell patterns in Plasmodium falciparum and P. vivax infections

Lymphocyte subset distributions and activation in the peripheral blood were studied in 39 patients with acute malaria and 16 healthy controls from Addis Ababa and Nazareth, Ethiopia. As confirmed by polymerase chain reaction (PCR), 15 patients were infected with Plasmodium falciparum (Pf ), 17 with P. vivax (Pv) and seven were double-infected (Di) with both Pf and Pv. Three-colour flow cytometry was used for phenotyping. Total leucocyte and lymphocyte counts were lower in malaria patients than in controls. The T cell count was reduced in Pf patients, while in the Pv and Di patients there was a reduction in the natural killer (NK) cell count. The CD4/CD8 ratio remained unchanged. γδ⁺ T cells were significantly elevated in Pf and Di patients, but not in Pv patients. The increase in γδ⁺ T cells was mostly due to an increase in Vδ1⁺ cells. Analyses of cellular activation indicated by the expressions of CD25 and HLA-DR revealed significantly higher numbers of activated CD3⁺ cells, including γδ⁺ T cells, in all patient groups compared with controls. Our results thus indicate that in acute malaria illness there is a complex pattern of change in lymphocyte subset distribution and activation, including γδ⁺ T cells. These patterns in Pf infection seem to be distinct from those in Pv infection.     

Early Deletion and Late Positive Selection of T-Cells Expressing a Male-Specific Receptor in T-Cell Receptor Transgenic Mice

The ontogeny of T cells in T-cell receptor (TCR) transgenic mice, which express a transgenic αβ heterodimer, specific for the male (H-Y) antigen in association with H-2D^b, was determined. The transgenic α chain was expressed on about 10% of the fetal thymocytes on day 14 of gestation. About 50% of day-15 fetal thymocytes expressed both α and β transchains and virtually all fetal thymocytes expressed the transgenicαβ heterodimer by day 17. The early expression of the transgenic TCR on CD4^-8^- thymocytes prevented the development of γδ cells, and led to accelerated growth of thymocytes and an earlier expression of CD4 and CD8 molecules. Up to day 17, no significant differences in T-cell development could be detected between female and male thymuses. By day 18 of gestation, the male transgenic thymus contained more CD4^-8^- thymocytes than the female transgenic thymus. The preponderance of CD4^-8^- thymocytes in the male transgenic thymus increased until birth and was a consequence of the deletion of the CD4⁺8⁺ thymocytes and their CD4^-8⁺ precursors. By the time of birth, the male transgenic thymus contained half the number of cells as the female transgenic thymus. The deletion of autospecific precursor cells in the male transgenic mouse began only at day 18 of gestation, despite the fact that the ligand could already be detected by day 16.The preferential accumulation of CD4^-8⁺ T cells, which expressed a high density of the transgenic TCR, occurred only after birth and was .obvious in 6-week-old female thymus. These data support the hypothesis that the positive selection of T cells expressing this transgenic heterodimer may involve two steps, i.e., the commitment of CD4⁺8⁺ thymocytes to the CD4^-8⁺ lineage following the interaction of the transgenic TCR with restricting major histocompatibility molecules, followed by a slow conversion of CD4⁺8⁺ thymocytes into CD4^-8⁺ T cells.In normal mice, the precursors of CD⁺4⁺8 and single positive thymocytes have the CD4^-8^- CD3^-J11d⁺ (or M1/69 ⁺) phenotype. Because of the early expression of the transgenic αβ heterodimer, this population was not detected in adult transgenic mice. All CD4^-8^- M1/ 69⁺ cells expressed the transgenic receptor associated with CD3 and could be readily grown in media containing T-cell lectins and interleukin 2.     

Enhanced Allergic Inflammation of Der p 2 Affected by Polymorphisms of MD-2 Promoter

Purpose

Myeloid differentiation-2 (MD-2) has been associated with endotoxin and inflammatory disorders because it can recognize lipopolysaccharide (LPS) binding and attenuate Toll-like receptor 4 (TLR4)-mediated signaling. However, its role in allergic inflammation has yet to be clarified. We examined whether single nucleotide polymorphisms (SNPs) in MD-2 promoter can affect MD-2 expression and aimed to clarify the relationship between Der p 2 allergy and SNPs of MD-2 promoter.

Methods

The function of SNPs of MD-2 promoter and the effects of cytokines and immunoglobulin on the secretion and mRNA expression were investigated in 73 allergic subjects with different MD-2 gene promoter variants. Peripheral blood mononuclear cells were cultured with or without LPS in the presence of Dermatophagoides pteronyssinus group 2 allergen (Der p 2), followed by mRNA extraction and cytokine expression analysis. The culture supernatants were collected for cytokine measurement.

Results

Patients with the MD-2 promoter SNPs (rs1809441/rs1809442) had increased mRNA expressions of MD-2, ε heavy chain of IgE (Cε), and interleukin (IL)-8; however, only MD-2 and IL-8 were further up-regulated after Der p 2 stimulation. Patients with SNPs of MD-2 promoter tended to have high levels of IL-1β, IL-6, IL-8, IL-10, and tumor necrosis factor (TNF)-α after Der p 2 and LPS stimulation. Increased secretions of IL-6, IL-8, and IL-10 were found to be up-regulated by Der p 2 stimulation, and an increased secretion of IFN-γ and decreased secretion of IL-4 were noted after LPS stimulation.

Conclusions

The high levels of proinflammatory cytokines secreted by Der p 2 were predetermined by MD-2 promoter SNPs (rs1809441/rs1809442). Through cytokine secretion by Der p 2 and LPS, these SNPs may serve as an indicator of the pathological phenotype of Der p 2-induced allergic inflammation.     

–308 G/A TNF-α gene polymorphism influences the course of basal cell carcinoma in a Polish population

Introduction

The etiopathogenesis of basal cell carcinoma (BCC) is multifactorial. The TNF-α gene seems to be an interesting gene candidate for BCC susceptibility because of the proinflammatory and immunosuppressive properties of its product. The aim of the study was to assess the frequency of –308 G/A and –238 G/A gene polymorphisms in the TNF-α gene and serum levels of cytokine in patients with BCC.

Material and methods

The study included 176 (94 women, 82 men) patients with BCC and 261 healthy volunteers. –308 G/A and –238 G/A TNF-α polymorphisms were analyzed using the amplification refractory mutation system-polymerase chain reaction method (ARMS-PCR). Serum concentrations of TNF-α were measured using ELISA.

Results

There was no statistically significant association between allele, genotype and haplotype frequencies in BCC patients in comparison with controls. Occurrence of the –308 TNF-α A allele or GA genotype in the group of patients with BCC increases risk of recurrence of tumor recurrence (OR = 4.8, 95% CI: 1.6–13.9, p = 0.004 and OR = 4.97, 95% CI: 1.7–14.5, p = 0.004). Moreover, –308 TNF-α GG genotype decreased risk of recurrence (OR = 0.2, 95% CI: 0.07–0.6, p = 0.004). The –238/–308 GA haplotype was connected with increased risk of recurrence (OR = 4.36, 95% CI: 1.49–12.7, p = 0.007). We also found significantly higher TNF-α levels among BCC patients in comparison with controls (p = 0.004).

Conclusions

The obtained results did not confirm the role of the –308 G/A and –238 G/A TNF-α gene polymorphisms in BCC development, but the presence of the A allele or GA genotype in –308 G/A TNF-α gene polymorphism may have an impact on the course of the disease.     

Squamosamide derivative FLZ inhibits TNF-α-induced ICAM-1 expression via down-regulation of the NF-κB signaling pathway in ARPE-19 cells

Dysfunction of the retinal pigment epithelium (RPE) resulting from chronic inflammation is implicated in the pathogenesis of age-related macular degeneration (AMD). It has been reported that tumor necrosis factor-α (TNF-α) could induce intercellular adhesion molecule-1 (ICAM-1) expression in RPE cells. FLZ, a novel synthetic squamosamide derivative from a Chinese herb, Annona glabra, has displayed significant anti-inflammatory activity. However, the effects of FLZ on TNF-α-induced ICAM-1 expression in RPE cells remain unknown. Therefore, in the present study, we evaluated the effects of FLZ on TNF-α-induced ICAM-1 expression in RPE cells. We found that FLZ prevented TNF-α-induced ICAM-1 expression and the ability of monocytes to adhere to ARPE-19 cells induced by TNF-α. Furthermore, FLZ inhibited TNF-α-induced NF-κB p65 expression, as well as phosphorylation of IκBα in ARPE-19 cells. Taken together, these results suggest that FLZ inhibited TNF-α-induced ICAM-1 expression through blocking NF-κB signaling pathway in ARPE-19 cells. Thus, FLZ could be used for designing novel therapeutic agents against AMD.     

α1-Antitrypsin modifies general natural killer cell interactions with dendritic cells and specific interactions with islet β-cells in favour of protection from autoimmune diabetes

The autoimmune destruction of pancreatic β-cells is the hallmark of type 1 diabetes (T1D). Failure of anti-CD3 antibodies to provide long-lasting reversal of T1D and the expression of a natural killer (NK) cell ligand on β-cells suggest that NK cells play a role in disease pathogenesis. Indeed, killing of β-cells by NK cells has been shown to occur, mediated by activation of the NK cell activating receptor, NKp46. α1-Antitrypsin (AAT), an anti-inflammatory and immunomodulatory glycoprotein, protects β-cells from injurious immune responses and is currently evaluated as a therapeutic for recent onset T1D. Although isolated T lymphocytes are not inhibited by AAT, dendritic cells (DC) become tolerogenic in its presence and other innate immune cells become less inflammatory. Yet a comprehensive profile of NK cell responses in the presence of AAT has yet to be described. In the present study, we demonstrate that AAT significantly reduces NK cell degranulation against β-cells, albeit in the whole animal and not in isolated NK cell cultures. AAT-treated mice, and not isolated cultured β-cells, exhibited a marked reduction in NKp46 ligand levels on β-cells. In related experiments, AAT-treated DC exhibited reduced inducible DC-expressed interleukin-15 levels and evoked a weaker NK cell response. NK cell depletion in a T1D mouse model resulted in improved β-cell function and survival, similar to the effects observed by AAT treatment alone; nonetheless, the two approaches were non-synergistic. Our data suggest that AAT is a selective immunomodulator that retains pivotal NK cell responses, while diverting their activities away from islet β-cells.     

Macrophage nitric oxide synthase (NOS) activation by Nocardia opaca fractions and 15- and 56-kD isolated antigens

The Gram-positive bacterium, Nocardia opaca, is a source of substances with adjuvant effect, ability to stimulate macrophages and natural killer cells for enhanced cytotoxity and cytokine production and B lymphocytes for polyclonal immunoglobulin secretion. We determined the immunogenicity of isolated N. opaca fractions and prepared MoAbs against immunogenic water-soluble mitogen (NWSM). Two main proteins of molecular mass 15 and 56 kD were detected in Western blot analysis and isolated by affinity chromatography using anti-NWSM MoAb B7/7. Both these isolated nocardial antigens were found to stimulate mouse peritoneal macrophage NOS. The effect of 5 μg NWSM was comparable to that of 5 μg lipopolysaccharide (LPS) or 20 U of interferon-gamma (IFN-γ) added to cell cultures. The MoAb B7/7 decreased NO₂⁻ production induced by NWSM or by isolated nocardial antigens, but did not significantly influence the production elicited by LPS or IFN-γ. On the other hand, NOS activation by NWSM was not affected by anti-IFN-γ MoAb. The possible independent pathway for IFN-γ and NWSM macrophage activation is discussed.