Unveiling antimicrobial resistance in Chilean fertilized soils: a One Health perspective on environmental AMR surveillance

Antimicrobial resistance (AMR) poses a significant threat to humans and animals as well as the environment. Within agricultural settings, the utilization of antimicrobial agents in animal husbandry can lead to the emergence of antimicrobial resistance. In Chile, the widespread use of animal-derived organic amendments, including manure and compost, requires an examination of the potential emergence of AMR resulting from their application. The aim of this research was to identify and compare AMR genes found in fertilized soils and manure in Los Andes city, Chile. Soil samples were collected from an agricultural field, comprising unamended soils, amended soils, and manure used for crop fertilization. The selected genes (n = 28) included genes associated with resistance to beta-lactams, tetracyclines, sulfonamides, polymyxins, macrolides, quinolones, aminoglycosides, as well as mobile genetic elements and multidrug resistance genes. Twenty genes were successfully identified in the samples. Tetracycline resistance genes displayed the highest prevalence, followed by MGE and sulfonamides, while quinolone resistance genes were comparatively less abundant. Notably, blaOXA, sulA, tetO, tetW, tetM, aac (6) ib., and intI1, exhibited higher frequencies in unamended soils, indicating their potential persistence within the soil microbiome and contribution to the perpetuation of AMR over time. Given the complex nature of AMR, it is crucial to adopt an integrated surveillance framework that embraces the One Health approach, involving multiple sectors, to effectively address this challenge. This study represents the first investigation of antimicrobial resistance genes in agricultural soils in Chile, shedding light on the presence and dynamics of AMR in this context.

One Welfare: Assessing the Effects of Drought and the COVID-19 Pandemic on Farmers' Well-Being and Their Perception of Goats' Welfare

Considering the interconnections between human well-being, animal welfare, and the environment, this study aimed to investigate the impacts of drought and the COVID-19 pandemic on small-scale goat farmers' well-being and their perception of goats' welfare following the One Welfare framework. Using a telephone survey, close-ended questions, and Likert scales, we assessed the impacts of drought and the COVID-19 pandemic on human well-being and animal welfare in the Coquimbo region of Chile. The DASS-21 questionnaire was used to evaluate farmers' mental health. Goat farmers perceived the scarcity of water and food for animals as factors that negatively affected animal productivity and welfare and caused an increase in farmers' stress levels. Farmers who had not been visited by a veterinarian showed higher levels of stress than those who received one visit during the year (M = 10 vs. 2, p = 0.025). Additionally, farmers who perceived better welfare of their animals showed lower levels of depression (rs = -0.17, p = 0.048), anxiety (rs = -0.21, p = 0.016), and stress (rs = -0.33, p < 0.001). These findings emphasize the importance of addressing farmers' mental health and veterinary support as crucial aspects to ensure both goat welfare and farm productivity.

Identification of Coxiella burnetii in Tank Raw Cow Milk: First Findings from Chile

Coxiella burnetii causes Q fever, an important zoonotic disease, and exposure is mainly associated with inhalation of contaminated aerosols. In South America, no systematic studies have been carried out. In Chile, the only official record of Q fever has been an outbreak of occupational context occurring in 1998 with eight confirmed human cases, all workers in the Agriculture and Livestock Service. Recently, in 2017 a Q fever outbreak was reported from dairy farm workers in two regions in southern Chile. This study determined the presence of C. burnetii in bulk tank milk samples from dairy farms obtained during this outbreak. A duplex real time quantitative PCR assay with primers and probes targeting two different gene sequences, IS1111 and com1, was used for diagnosis. C. burnetii was detected in 2 of 105 samples analyzed (2.1%). These results pose a potential public health risk as the milk from these farms was sold to the local human population. This is the first report on detecting C. burnetii in raw tank milk samples in Chile.

Trypanosoma cruzi cleaves galectin-3 N-terminal domain to suppress its innate microbicidal activity

Galectin-3 is the best-characterized member of galectins, an evolutionary conserved family of galactoside-binding proteins that play central roles in infection and immunity, regulating inflammation, cell migration and cell apoptosis. Differentially expressed by cells and tissues with immune privilege, they bind not only to host ligands, but also to glycans expressed by pathogens. In this regard, we have previously shown that human galectin-3 recognizes several genetic lineages of the protozoan parasite Trypanosoma cruzi, the causal agent of Chagas' disease or American trypanosomiasis. Herein we describe a molecular mechanism developed by T. cruzi to proteolytically process galectin-3 that generates a truncated form of the protein lacking its N-terminal domain - required for protein oligomerization - but still conserves a functional carbohydrate recognition domain (CRD). Such processing relies on specific T. cruzi proteases, including Zn-metalloproteases and collagenases, and ultimately conveys profound changes in galectin-3-dependent effects, as chemical inhibition of parasite proteases allows galectin-3 to induce parasite death in vitro. Thus, T. cruzi might have established distinct mechanisms to counteract galectin-3-mediated immunity and microbicide properties. Interestingly, non-pathogenic T. rangeli lacked the ability to cleave galectin-3, suggesting that during evolution two genetically similar organisms have developed different molecular mechanisms that, in the case of T. cruzi, favoured its pathogenicity, highlighting the importance of T. cruzi proteases to avoid immune mechanisms triggered by galectin-3 upon infection. This study provides the first evidence of a novel strategy developed by T. cruzi to abrogate signalling mechanisms associated with galectin-3-dependent innate immunity.

Optimization of florfenicol dose against Piscirickettsia salmonis in Salmo salar through PK/PD studies

Salmonid Rickettsial Septicemia (SRS) is the disease of greatest economic importance in the Chilean salmon farming industry, causing high mortality in fish during the final stage of their productive cycle at sea. Since current, commercially available vaccines have not demonstrated the expected efficacy levels, antimicrobials, most commonly florfenicol, are still the main resource for the treatment and control of this pathogen. The aim of this study was to determine the most appropriate single dose of florfenicol, administered through medicated feed, for the treatment of Piscirickettsia salmonis (P. salmonis), using pharmacokinetic/pharmacodynamic (PK/PD) models. Previously, Minimum Inhibitory Concentrations (MICs) of florfenicol were determined for 87 P. salmonis isolates in order to define the epidemiological cut-off point (CO_WT). The most commonly observed MIC was 0.125 μg mL^-1 (83.7%). The CO_WT value was 0.25 μg mL^-1 with a standard deviation of 0.47 log₂ μg mL^-1 and 0.36 log₂ μg mL^-1, for Normalized resistance interpretation (NRI) method and ECOFFinder method, respectively. A MIC of 1 μg mL^-1 was considered the pharmacodynamic value (PD) to define PK/PD indices. Three doses of florfenicol were evaluated in fish farmed under controlled conditions. For each dose, 150 fish were used and blood plasma samples were collected at different time points (0–48 hours). PK parameters were obtained from curves representing plasma concentrations as a function of time. The results of Monte Carlo simulation indicate that at a dose of 20 mg/Kg l.w. of florfenicol, administered orally as medicated feed, there is 100% probability (PTA) of achieving the desired efficacy (AUC_0-24h/MIC>125). According to these results, we suggest that at the indicated dose, the PK/PD cut-off point for florfenicol versus P. salmonis could be 2 μg mL^-1 (PTA = 99%). In order to assess the indicated dose in Atlantic salmon, fish were inoculated with P. salmonis LF-89 strain and then treated with the optimized dose of florfenicol, 20 mg/Kg bw for 15 days.

Genetic and phenotypic evidence of the Salmonella enterica serotype Enteritidis human-animal interface in Chile

Salmonella enterica serotype Enteritidis is a worldwide zoonotic agent that has been recognized as a very important food-borne bacterial pathogen, mainly associated with consumption of poultry products. The aim of this work was to determine genotypic and phenotypic evidence of S. Enteritidis transmission among seabirds, poultry and humans in Chile. Genotyping was performed using PCR-based virulotyping, pulse-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST). Pathogenicity-associated phenotypes were determined with survival to free radicals, acidic pH, starvation, antimicrobial resistance, and survival within human dendritic cells. As result of PCR and PFGE assays, some isolates from the three hosts showed identical genotypic patterns, and through MLST it was determined that all of them belong to sequence type 11. Phenotypic assays show diversity of bacterial responses among isolates. When results were analyzed according to bacterial host, statistical differences were identified in starvation and dendritic cells survival assays. In addition, isolates from seabirds showed the highest rates of resistance to gentamycin, tetracycline, and ampicillin. Overall, the very close genetic and phenotypic traits shown by isolates from humans, poultry, and seabirds suggest the inter-species transmission of S. Enteritidis bacteria between hosts, likely through anthropogenic environmental contamination that determines infection of seabirds with bacteria that are potentially pathogenic for other susceptible organism, including humans.

Short communication: Sensory profile of raw goat milk cheeses made with artisan kid rennet pastes from commercial-weight animals: alternative to farmhouse goat cheeses

The loss of traditional kid rennet pastes in the Canary Islands (Spain), as in many other regions, is most likely due to the custom of using abomasa from very young animals killed below desirable commercial weight. In addition, the reasonable price of commercial rennets (CR) has resulted in the loss of typical sensory characteristics for most farmhouse raw goat milk cheeses, placing them at a disadvantage when local and international markets are full of different cheeses, often with aggressive marketing strategies. This paper analyzes the sensory characteristics of raw goat milk cheeses made with rennet pastes prepared from commercial kid abomasa in 2 ways: dried while full of ingested milk [full, commercial, artisan kid rennet (FCKR)], or dried after being emptied of ingested milk and refilled with raw goat milk [empty, commercial, artisan kid rennet (ECKR)]. This latter practice allows the use of empty abomasa, or abomasa with grass, soil, and so on. Sensory profiles of cheeses made with FCKR and ECKR rennets were compared with those made with CR by an expert panel (n=7). The FCKR and ECKR cheeses had similar sensory profiles. Although scores for FCKR cheeses were somewhat higher than for ECKR cheeses, they were in the range found for traditional cheeses made with rennet prepared with abomasa from very young animals. The sensory profile of CR cheeses was very different. Almost 90% of consumer panelists (n=90) preferred cheeses made with the experimental rennet pastes. These results demonstrate the possibility to prepare artisan rennet pastes from commercial-weight kids in an easy way for farmhouse cheese makers using local resources that would otherwise be destroyed in abattoirs.

Serotype-associated polymorphisms in a partial rpoB gene sequence of Salmonella enterica

Salmonella enterica is a zoonotic bacterium with more than 2500 serotypes, which affect a wide range of hosts and produce diverse clinical outcomes. Strain identification usually involves costly and time-demanding procedures. This paper describes the sequencing of a rpoB hypervariable gene segment (847 bp) that allows identification of serotypes in S. enterica strains isolated from several hosts. The nucleotide similarity values among S. enterica serotypes ranged from 98.23% to 99.88%, with potential usefulness for devising a simple one-step sequencing as a first approach for identification of S. enterica strains. In conclusion, the analysis of polymorphisms in the partial rpoB sequence can discriminate S. enterica strains at the subspecies level.

Identification of diverse Salmonella serotypes, virulotypes, and antimicrobial resistance phenotypes in waterfowl from Chile

Salmonella enterica is a pathogen with a wide host-range that presents great concern in developed and developing countries. To determine and characterize Salmonella strains found in Chile's waterfowl, we sampled 758 birds along 2000 km of the Chilean coast. In this sample, 46 isolates from 10 serotypes were detected, several with multidrug resistance phenotypes and different combinations of virulence-associated genes (virulotypes). These results suggest that Salmonella infection in waterfowl in Chile could have impacts on public and animal health.

EGFR signaling upregulates expression of microsomal prostaglandin E synthase-1 in cancer cells leading to enhanced tumorigenicity

In this report we describe the contribution of prostaglandin E(2) (PGE(2)) derived from the inducible microsomal PGE-synthase type-1 (mPGES-1) to the epidermal growth factor receptor (EGFR) oncogenic drive in tumor epithelial cells and in tumor-bearing mice. EGFR stimulation upregulated expression of mPGES-1 in HT-29, A431 and A549 cancer cells. Egr-1, a transcription factor induced by EGF, mediated this response. The Egr-1 rise provoked the overexpression of mPGES-1 messenger and protein, and enhanced PGE(2) formation. These changes were suppressed either by silencing Egr-1, or by upstream blockade of EGFR or ERK1/2 signals. Further, in a clonogenic assay on tumor cells, EGF induced a florid tumorigenic phenotype, which regressed when mPGES-1 was silenced or knocked down. EGF-induced mPGES-1 overexpression in epithelial cell reduced E-cadherin expression, whereas enhancing that of vimentin, suggesting an incipient mesenchymal phenotype. Additionally, inhibiting the EGFR in mice bearing the A431 tumor, the mPGES-1 expression and the tumor growth, exhibited a parallel decline. In conclusion, these findings provide novel evidence that a tight cooperation between the EGF/EGFR and mPGES-1 leads to a significant tumorigenic gain in epithelial cells, and provide clues for controlling the vicious association.

Physicochemical analysis of full-fat, reduced-fat, and low-fat artisan-style goat cheese

The objective of this study was to examine the physicochemical properties of cheese elaborated via traditional artisan methods using goat milk containing 5, 1.5, or 0.4% fat and ripened for 1, 7, 14, or 28 d. Seventy-two cheeses were produced (2 batches x 3 fat levels x 4 ripening times x triplicate). Proximal composition, pH, texture analysis, and color were recorded in each cheese. Protein and moisture were increased in cheese, and fat and fat in DM were decreased with decreasing fat in milk. Internal and external pH was higher in low-fat and reduced-fat cheese, and pH values decreased during the first 2 wk of ripening but increased slightly on d 28. Cheese fracturability, cohesiveness, masticability, and hardness increased with decreasing fat, whereas elasticity and adhesiveness decreased. Cheese lightness and red and yellow indexes decreased with decreasing fat content; during ripening, lightness decreased further but yellow index increased.

Alternatives for Improving Physical, Chemical, and Sensory Characteristics of Goat Cheeses: The Use of Arid-Land Forages in the Diet

To establish the effect of an alternative diet on the quality of Majorero cheese, the basic physicochemical parameters, fatty acid profile, and sensory characteristics were studied. Two groups of 20 Majorero goats were fed 2 different diets: a forage diet (DF), which had a high ratio of long fiber to concentrates (65:35), and a concentrate diet (DC), with a low ratio of long fiber to concentrates (35:65). The DF dietary fiber was supplied by native forages adapted to arid land. A total of 42 Majorero goat cheeses were used for this study: 21 in the DF group and 21 in the DC group. Seven cheeses from each group were tested after 2, 15, and 60 d of ripening. The milk produced by goats fed the DF diet had a higher fat concentration. No significant differences were observed in the milk fatty acid profile. The diet affected the chemical composition of the cheese in pH and fat content, and fat was significantly higher in cheeses made from DF milk than those from DC milk. Dietary characteristics had important effects on the medium-chain fatty acid composition (C6 to C14) of the cheese fat, giving DF cheeses the specific goat's milk flavor that is sought after for this type of cheese. The fatty acid composition (%) differed substantially among different ripening times. The DF cheeses were more appreciated by the panelists, as they had a greater variety of odors and flavors than the DC cheeses. The DF hard cheeses were described as having vegetable and fruity tones as well as tones of hay and dried fruit.

The efficacy of photochemical treatment with methylene blue and light for the reduction of Trypanosoma cruzi in infected plasma

BACKGROUND AND OBJECTIVES

Chagas disease is a transfusion-transmitted infection. This study evaluates the efficacy of a methylene blue (MB) and light system for reducing the viability of Trypanosoma cruzi in plasma. MATERIALS AND METHODS Trypanosoma cruzi strains were spiked in plasma pools. Treatment arms included combined filtration, MB, light and freezing. Post-treatment parasite viability was assayed through in vitro cultures and in vivo inoculation in inducible nitric oxide synthase- and interferon-gamma-receptor-deficient mice.

RESULTS

The filtration, MB and light combined treatment showed a log reduction of > 3.4 in in vitro cultures, and log reductions that ranged from > 4.9 to > 5.8 in deficient mice inoculated with different T. cruzi strains.

CONCLUSION

The treatment of plasma units with the MB and light system reduces the T. cruzi burden and could be useful in preventing transfusion-transmitted Chagas disease.

Bombesin induces cyclooxygenase-2 expression through the activation of the nuclear factor of activated T cells and enhances cell migration in Caco-2 colon carcinoma cells

Cyclooxygenase-2 (Cox-2), the gastrin-release peptide (GRP) and its cognate receptor (GRP-R) are overexpressed in a significant percentage of colorectal carcinomas and are associated with cell growth, invasiveness and tumor progression. However, a molecular link between all of them in adenocarcinomas has not been established. Here, we show that bombesin (BBS), a GRP homolog, stimulates the expression of Cox-2 mRNA and protein in human colon adenocarcinoma Caco-2 cells, resulting in enhanced release of prostaglandin E(2). These effects were markedly inhibited by the specific BBS antagonist RC-3940-II. BBS promotes the activation of the nuclear factor of activated T cells (NFAT) through a Ca(2+)/calcineurin (Cn)-linked pathway. Upon BBS stimulation, the NFATc1 isoform translocates into the nucleus with a concomitant increase in NFATc1 binding to two specific recognition sites in the promoter region of the Cox-2 gene. Furthermore, inhibition of Cn activity by the immunosuppressive drug cyclosporin A impaired NFAT activation and diminished Cox-2 expression in BBS-stimulated cells. Interestingly, BBS pretreatment strongly enhances the invasive capacity of carcinoma cells, effect which was inhibited by a Cox-2-specific inhibitor. These findings provide the first evidence for the involvement of the Ca(2+)/Cn/NFAT pathway in BBS-mediated induction of genes involved in colon carcinoma invasiveness such as Cox-2.

Encephalitozoon microsporidia modulates p53-mediated apoptosis in infected cells

Microsporidia are intracellular obligate parasites which have recently been found to be related to fungi. They have a unique extrusion apparatus that is able to inject the sporoplasm directly into the target cell without using receptors. Encephalitozoon microsporidia are a source of morbidity and mortality in humans. It has been suggested that microsporidia may modulate the host cell cycle and apoptosis. We report here that caspase-3 cleavage is inhibited at different times of Vero cell infection by Encephalitozoon microsporidia and that the phosphorylation and translocation of p53 to the nucleus, previous steps for the activation of this protein, do not occur after infection of Vero cells. Consequently, the transcriptional function of p53 is impaired during the infection cycle as demonstrated by luciferase reporter assays. Thus, to our knowledge, for the first time it is shown that an intracellular parasite may be able to multiply in the host cell without activating the p53 apoptotic pathway of that cell. However, changes in the expression of Bcl-2 or Bax levels were not observed.

Trypanosoma cruzi-induced molecular mimicry and Chagas' disease

Chagas' disease, caused by Trypanosoma cruzi, has been considered a paradigm of infection-induced autoimmune disease. Thus, the scarcity of parasites in the chronic phase of the disease contrasts with the severe cardiac pathology observed in approximately 30% of chronic patients and suggested a role for autoimmunity as the origin of the pathology. Antigen-specific and antigen-non-specific mechanisms have been described by which T. cruzi infection might activate T and B cells, leading to autoimmunity. Among the first mechanisms, molecular mimicry has been claimed as the most important mechanism leading to autoimmunity and pathology in the chronic phase of this disease. In this regard, various T. cruzi antigens, such as B13, cruzipain and Cha, cross-react with host antigens at the B or T cell level and their role in pathogenesis has been widely studied. Immunization with those antigens and/or passive transfer of autoreactive T lymphocytes in mice lead to clinical disturbances similar to those found in Chagas' disease patients. On the other hand, the parasite is becoming increasingly detected in chronically infected hosts and may also be the cause of pathology either directly or through parasite-specific mediated inflammatory responses. Thus, the issue of autoimmunity versus parasite persistence as the cause of Chagas' disease pathology is hotly debated among many researchers in the field. We critically review here the evidence in favor of and against autoimmunity through molecular mimicry as responsible for Chagas' disease pathology from clinical, pathological and immunological perspectives.

Components Detected by Means of Solid-Phase Microextraction and Gas Chromatography/Mass Spectrometry in the Headspace of Artisan Fresh Goat Cheese Smoked by Traditional Methods

The study of the headspace components of fresh smoked goat cheese, was carried out by means of solid-phase microextraction using a polyacrylate fiber followed by gas chromatography/mass spectrometry. The samples studied were six artisan Palmero cheeses manufactured following traditional methods and smoked using pine needles. The cheese regions studied were exterior, interior, and a cross section. In total, more than 320 components were detected, the exterior region being the richest in components, among which were acids, alcohols, esters, hydrocarbons, aldehydes, ketones, furan and pyran derivatives, terpenes and sesquiterpenes, nitrogen derivatives, phenol, guaiacol and syringol derivatives, ethers, and others. In addition to typical cheese components, typical smoke components were also detected; these latter were present especially in the headspace of the exterior region and only those in significant concentrations in the exterior region were also detected in the interior. The main components were acids and phenolic derivatives. These latter compounds play an important role in the flavor of this cheese, and their relative proportions together with the presence of specific smoke components derived from pine leaves may be considered of interest in order to distinguish this cheese from others smoked with different vegetable matter.

Immunological properties of a DNA plasmid encoding a chimeric protein of herpes simplex virus type 2 glycoprotein B and glycoprotein D

A DNA plasmid containing a chimeric sequence encoding both herpes simplex virus type 2 (HSV-2) glycoprotein B (gB) and glycoprotein D (gD) external domains (pcgDB) was used to immunize BALB/c mice against genital HSV-2 infection. To determine the efficacy of this vaccine, groups of mice immunized with the pcgDB plasmid were compared with animals immunized with plasmids corresponding to the individual proteins (pcgBt or pcgDt), administered separately or in combination (pcgBt + pcgDt). We studied the response of the different mouse groups to viral challenge by analyzing clinical disease (vaginitis), serum antibody levels, as well as lymphoproliferative responses and cytokine production by spleen cells. Increased IFN-gamma levels correlated with prolonged survival in mice immunized with the plasmid pcgDB, relative to mice immunized with plasmids coding for the individual proteins alone or in combination. Our results show that immunization with the plasmid encoding the chimeric protein is advantageous over separate proteins. These findings may have important implications for the development of multivalent DNA vaccines against HSV and other complex pathogens.

Antibodies to an epitope from the Cha human autoantigen are markers of Chagas' disease

Chagas' disease is a prevalent disease in South America that is thought to have an autoimmune etiology. We previously identified human Cha as a new autoantigen recognized by chagasic sera. Those sera recognized an epitope spanning amino acids 120 to 129 of Cha, named R3. In the present study we have used the synthetic R3 peptide for the detection of serum immunoglobulin G antibodies from patients at different stages of Chagas' disease, including a therapeutically treated group. The immunoreactivity with R3 by enzyme-linked immunosorbent assay (ELISA) showed 92.4% sensitivity and 100% specificity for Chagas' disease sera. This sensitivity and specificity were higher than for any other autoantigen described to date. No anti-R3 antibodies were detected in sera from Leishmania-infected or idiopathic dilated cardiomyopathy patients or healthy controls from the same areas. Moreover, anti-R3 antibody reactivity detected by ELISA correlated with conventional serological tests as indirect immunofluorescence and ELISA assays with Trypanosoma cruzi extracts and other diagnostic tests as indirect hemagglutination. The levels of anti-R3 antibodies increased with progression and symptomatology of Chagas' disease. More interestingly, a statistically significant fall in anti-R3 antibody titer was observed in patients treated with antiparasitic drugs. Those results suggest that the presence of anti-R3 antibodies is a highly specific marker of Chagas' disease and that R3 ELISA could be helpful in the diagnosis and monitoring of this disease.

Phosphodiesterase 4 inhibitors prevent cytokine secretion by T lymphocytes by inhibiting nuclear factor-kappaB and nuclear factor of activated T cells activation

Blockade of phosphodiesterase 4 with rolipram reduced the production of tumor necrosis factor (TNF)-alpha, interleukin (IL)-5, IL-10, and IL-2 but poorly inhibited cell proliferation and interferon-gamma (IFN-gamma) production by activated human T cells. Addition of dibutyryl cAMP mimicked rolipram inhibitions on proliferation, IL-2, TNF-alpha, and IFN-gamma but not on IL-10 or IL-5 production. Moreover, the inhibitory effects of rolipram on proliferation, IFN-gamma, and TNF-alpha but not of IL-10 production can be prevented by a specific protein kinase A inhibitor. Rolipram and pentoxifylline, a nonspecific phosphodiesterase inhibitor, decreased transcription of IL-2 and TNF-alpha promoters in transiently transfected normal T cells. Moreover, they inhibited the activation of nuclear factor-kappaB (NF-kappaB) and nuclear factor of activated T cells (NFAT) and stimulated activator protein-1 (AP-1) and cAMP response element-binding proteins (CREBs). In contrast, dibutyryl cAMP inhibited NF-kappaB but not NFAT activation. Thus, our data indicate that blockade of phosphodiesterase 4 regulates transcription of a particular cytokine through inhibition of NF-kappaB and NFAT, and stimulation of AP-1 and CREB.

Binding specificity of mannose-specific carbohydrate-binding protein from the cell surface of Trypanosoma cruzi

The sugar binding specificity of the recently described mannose-specific carbohydrate-binding proteins (CBP) isolated to homogeneity from both the epimastigote and trypomastigote stages of the pathogenic protozoa Trypanosoma cruzi has been studied by quantitative hapten inhibition of the biotinylated CBPs to immobilized thyroglobulin using model oligosaccharides. The results clearly show a differential specificity toward high-mannose glycans between the CBPs from the two developmental stages. Thus, the isolated CBP from epimastigotes exhibited stronger affinity for higher mannose oligomers containing the Manalpha1-2Manalpha1-6Manalpha1-6 structure. Its affinity decreased, as did the number of mannose residues on the oligomer or removal of the terminal Manalpha1-2-linked mannose. By contrast the CBP isolated from the trypomastigote stage showed about 400-fold lower avidity than the epimastigote form, and contrary to it, it was slightly more specific toward Man5GlcNAc than Man9GlcNAc. Analysis of the interaction of epimastigote-Man-CBP with its ligands by UV difference spectroscopy indicates the existence of an extended binding site in that protein with a large enthalpic contribution to the binding. The thermodynamic parameters of binding were obtained by isothermal titration calorimetry and been found that the DeltaH values to be in good agreement with the van't Hoff values. The binding reactions are mainly enthalpically driven and exhibit enthalpy-enthropy compensation. In addition, analysis of the high-mannose glycans from different parts of the digestive tract of the reduviid insect vector of T. cruzi suggest a role of the CBP in the retention of the epimastigote stage in the anterior portion of the gut.

Tumor necrosis factor-alpha and nitric oxide in vertically HIV-1-infected children: implications for pathogenesis

We performed a cross-sectional study to investigate the plasma TNF-alpha and nitric oxide (NO) production in 44 vertically HIV-1-infected children, and the relationship with immunological status and viral replication. As a control group, 36 healthy, uninfected children were studied. Plasma TNF-alpha and NO levels were determined by ELISA. Viral load was quantified using standard assays. Cell proliferation, apoptosis and viral replication were evaluated in vitro by incorporation of (3H)-thymidine, flow cytometry and p24 antigen, respectively. Higher plasma TNF-alpha and NO levels were observed in HIV-1-infected children compared with healthy controls. We found a very strong correlation between plasma TNF-alpha and NO levels in HIV-1-infected children (r = 0.98; p < 0.001). Moreover, HIV-1-infected children with higher viral load (> 4.7 log10) showed higher TNF-alpha and NO levels than those with viral load below this threshold. Interestingly, we detected inducible nitric oxide synthase (iNOS) mRNA in T-lymphocytes from HIV-1-infected children. To address their possible patho-physiological significance, we tested the in vitro effects of NO and TNF-alpha in HIV-1 replication. Addition of TNF-alpha and NO donors to mitogen-activated, HIV-1-infected PBMC cultures produced a significant increase in viral replication. Moreover, HIV-1 replication in mitogen-stimulated, PBMC cultures was partially inhibited by iNOS specific inhibitors, and a neutralising, anti-TNF-alpha monoclonal antibody. Our results indicate that TNF-alpha and NO correlated with high viral load in HIV-1-infected children and favoured HIV-1 in vitro replication. These data suggest a detrimental role of NO in HIV-1 infection, and that NOS inhibitors may have some therapeutic benefit in HIV-1-infection.

Cot kinase induces cyclooxygenase-2 expression in T cells through activation of the nuclear factor of activated T cells

Cyclooxygenase-2 (COX-2) is induced in human T lymphocytes upon T cell receptor triggering. Here we report that Cot kinase, a mitogen-activated protein kinase kinase kinase involved in T cell activation, up-regulates COX-2 gene expression in Jurkat T cells. Induction of COX-2 promoter activity by Cot kinase occurred mainly through activation of the nuclear factor of activated T cells (NFAT). Mutation of the distal (-105/-97) and proximal (-76/-61) NFAT response elements in the COX-2 promoter abolished the activation induced by Cot kinase. Even more, coexpression of a dominant negative version of NFAT inhibited Cot kinase-mediated COX-2 promoter activation, whereas cotransfection of a constitutively active version of the calcium-dependent phosphatase calcineurin synergizes with Cot kinase in the up-regulation of COX-2 promoter-driven transcription. Strikingly, Cot kinase increased transactivation mediated by a GAL4-NFAT fusion protein containing the N-terminal transactivation domain of NFATp. In contrast to phorbol ester plus calcium ionophore A23187, Cot kinase increases both COX-2 promoter activity and NFAT-mediated transactivation in a cyclosporin A-independent manner. These data indicate that Cot kinase up-regulates COX-2 promoter-driven transcription through the NFAT response elements, being the Cot kinase-induced NFAT-dependent transactivation presumably implicated in this up-regulation.

Regulation of nuclear factor kappa B transactivation. Implication of phosphatidylinositol 3-kinase and protein kinase C zeta in c-Rel activation by tumor necrosis factor alpha

Transactivation by c-Rel (nuclear factor kappaB) was dependent on phosphorylation of several serines in the transactivation domain, indicating that it is a phosphorylation-dependent Ser-rich domain. By Ser --> Ala mutational and deletion analysis, we have identified two regions in this domain: 1) a C-terminal region (amino acids 540-588), which is required for basal activity; and 2) the 422-540 region, which responds to external stimuli as tumor necrosis factor (TNF) alpha or phorbol myristate acetate plus ionomycin. Ser from 454 to 473 were shown to be required for TNFalpha-induced activation, whereas Ser between 492 and 519 were required for phorbol myristate acetate plus ionomycin activation. Phosphatidylinositol 3-kinase (PI3K) and protein kinase C (PKC) zeta were identified as downstream signaling molecules of TNFalpha-activation of c-Rel transactivating activity. Interestingly, dominant negative forms of PI3K inhibited PKCzeta activation and dominant negative PKCzeta inhibited PI3K-mediated activation of c-Rel transactivating activity, indicating a cross-talk between both enzymes. We have identified the critical role of different Ser for PKCzeta- and PI3K-mediated responses. Interestingly, those c-Rel mutants not only did not respond to TNFalpha but also acted as dominant negative forms of nuclear factor kappaB activation.

Regulation of human immunodeficiency virus type 1 replication in human T lymphocytes by nitric oxide

Addition of nitric oxide (NO) donors to mitogen-activated human immunodeficiency virus type 1 (HIV-1)-infected peripheral blood mononuclear cultures produced a significant increase in virus replication, and this effect was not associated with a change in cell proliferation. This effect was only observed with T-tropic X4 or X4R5 virus but not with R5 virus. Moreover, HIV-1 replication in mitogen-stimulated cultures was partially prevented by the specific inhibitors of the inducible nitric oxide synthase (iNOS). NO donors also enhanced HIV-1 infection of the human T-cell lines, Jurkat and MT-2. We have also observed that NO leads to an enhancement of HIV-1 replication in resting human T cells transfected with a plasmid carrying the entire HIV-1 genome and activated with phorbol ester plus ionomycin. Thus, in those cultures NO donors strongly potentiated HIV-1 replication in a dose-dependent manner, up to levels comparable to those with tumor necrosis factor alpha (TNF-alpha) stimulation. Furthermore, iNOS inhibitors decreased HIV-1 replication in HIV-1-transfected T cells to levels similar to those obtained with neutralizing anti-TNF-alpha antibodies. Moreover, HIV-1 replication induced iNOS and TNF-alpha transcription in T cells and T-cell lines. Interestingly, NO donors also stimulated long terminal repeat (LTR)-driven transcription whereas iNOS inhibitors partially blocked TNF-alpha-induced LTR transcription. Therefore, our results suggest that NO is involved in HIV-1 replication, especially that induced by TNF-alpha.

Dominant T- and B-cell epitopes in an autoantigen linked to Chagas' disease

In Chagas' disease caused by Trypanosoma cruzi, a paradigm of autoimmune disease, both autoantibodies and autoreactive T cells have been described. We have identified a novel dominant autoantigen, named Cha, recognized by the majority of sera from T. cruzi-infected humans and mice. We noted significant homologies between amino acids 120-129 of Cha, where the B-cell epitope maps, and an expressed sequence tag from T. cruzi, and also between amino acids 254-273 of Cha and a repeated amino acid sequence from the shed acute-phase antigen (SAPA) of T. cruzi. Moreover, T. cruzi-infected mice contain autoreactive T cells that can cross-react with Cha and the SAPA homologous peptides. Transfer of T cells from infected mice triggered anti-Cha (120-129) Ab production in naive recipients. Interestingly, heart tissue sections from those adoptive transferred mice showed cardiac pathology similar to T. cruzi-infected mice. Our results demonstrate the presence of both T- and B-cell cross-reactive epitopes in the Cha antigen. This dual mimicry may lead to T/B cell cooperation and give rise to a pathological immunodominant response against Cha in T. cruzi infected animals.

HIV-1 Tat inhibits IL-2 gene transcription through qualitative and quantitative alterations of the cooperative Rel/AP1 complex bound to the CD28RE/AP1 composite element of the IL-2 promoter

Dysregulation of cytokine secretion plays an important role in AIDS pathogenesis. Here, we demonstrate that expression of HIV-1 Tat protein in Jurkat cells induces a severe impairment of IL-2 but not TNF gene transcription. Interestingly, this inhibition correlates with the effect of the viral protein on the transactivation of the CD28RE/AP1 composite element (-164/-154), but not with that observed on the NFAT/AP1 site of the IL-2 gene promoter, neither with the effect on NF-kappa B- nor AP1-independent binding sites. Endogenous expression of Tat induced a decrease in the amount of the specific protein complex bound to the CD28RE/AP1 probe after PMA plus calcium ionophore stimulation. This effect was accompanied by qualitative alterations of the AP1 complex. Thus, in wild-type Jurkat cells, c-jun was absent from the complex, whereas in Tat-expressing cells, c-jun was increasingly recruited overtime. By contrast, similar amounts of c-rel and a small amount of NFAT1 were detected both in wild type and in Jurkat Tat(+) cells. Furthermore, Tat not only induced the participation of c-jun in the cooperative complex but also a decrease in its transactivation activity alone or in combination with c-rel. Thus, the interaction of Tat with the components of this rel/AP1 cooperative complex seems to induce quantitative and qualitative alterations of this complex as activation progresses, resulting in a decrease of IL-2 gene transcription. Altogether our results suggest the existence of tuned mechanisms that allow the viral protein to specifically affect cooperative interactions between transcription factors.

[Idiopathic retroperitoneal fibrosis]

OBJECTIVE

A case of idiopathic retroperitoneal fibrosis in a 34-year-old man with anemia and elevated erythrocyte sedimentation rate is presented.

METHODS/RESULTS

Ultrasound, CT and MRI evaluation and pathological study were performed. These diagnostic imaging techniques demonstrated an infiltrating mass in the upper portion of the abdomen which was resected. Histological and immunohistochemical studies of the surgical specimen demonstrated sclerosing retroperitonitis.

CONCLUSIONS

Idiopathic retroperitoneal fibrosis (Ormond's disease) is a rare disease entity whose etiology is obscure and is characterized by retroperitoneal fibrosis with inflammatory infiltrates composed of plasma cells, lymphocytes and eosinophils. This case is of interest due to its atypical location, and because the patient was young with no remarkable clinical history and only mild anemia and an elevated erythrocyte sedimentation rate.

Allelic selection of human IL-2 gene

The allelic expression of mouse IL-2 cannot be definitely extrapolated to what might happen in humans. Therefore, we investigated the regulation of allelic expression of the IL-2 gene in non-genetically manipulated human T lymphocytes by following natural allelic polymorphisms. We found a phenotypically silent punctual change in the human IL-2 at position 114 after the first nucleotide of the initiation codon, which represents a dimorphic polymorphism at the first exon of the IL-2 gene. This allowed the study by single-cell PCR of the regulation of the human IL-2 allelic expression in heterozygous CD4(+) T cells, which was found to be tightly controlled monoallelically. These findings may be used as a suitable marker for monitoring the IL-2 allelic contribution to effector activities and in immune responses against different infections or in pathological situations.

Induction of antibodies reactive to cardiac myosin and development of heart alterations in cruzipain-immunized mice and their offspring

Human and murine infection with Trypanosoma cruzi parasite is usually accompanied by strong humoral and cellular immune response to cruzipain, a parasite immunodominant antigen. In the present study we report that the immunization of mice with cruzipain devoid of enzymatic activity, was able to induce antibodies which bind to a 223-kDa antigen from a mouse heart extract. We identified this protein as the mouse cardiac myosin heavy chain by sequencing analysis. The study of IgG isotype profile revealed the occurrence of all IgG isotypes against cruzipain and myosin. IgG1 showed the strongest reactivity against cruzipain, whereas IgG2a was the main isotype against myosin. Anti-cruzipain antibodies purified by immunoabsorption recognized the cardiac myosin heavy chain, suggesting cross-reactive epitopes between cruzipain and myosin. Autoimmune response in mice immunized with cruzipain was associated to heart conduction disturbances. In addition, ultrastructural findings revealed severe alterations of cardiomyocytes and IgG deposit on heart tissue of immunized mice. We investigated whether antibodies induced by cruzipain transferred from immunized mothers to their offsprings could alter the heart function in the pups. All IgG isotypes against cruzipain derived from transplacental crossing were detected in pups' sera. Electrocardiographic studies performed in the offsprings born to immunized mothers revealed conduction abnormalities. These results provide strong evidence for a pathogenic role of autoimmune response induced by a purified T. cruzi antigen in the development of experimental Chagas' disease.

Mapping of genetic deletions on the long arm of chromosome 22 in human pancreatic adenocarcinomas

The molecular mechanisms of carcinogenesis in pancreatic cancer are still poorly understood, although the inactivation of tumor suppressor genes at multiple loci is suspected. We investigated the loss of heterozygosity (LOH) on chromosome 22 in pancreatic cancer by means of a PCR-based microsatellite analysis of archival paraffin-embedded histological sections in order to better define deleted region(s) and to test whether the NF-2 gene is involved. Using a panel of thirteen markers that spanned the long arm of chromosome 22, loss of heterozygosity was identified for at least one locus in 37% of investigated pancreatic adenocarcinomas. These deletions are clustered into two separate areas of the chromosome 22--one proximal to the NF-2 gene and one distal. The NF-2 gene itself is not involved. These regions are likely locations of tumor suppressor genes that may contribute to the development of pancreatic cancer.

Lectins from tropical sponges. Purification and characterization of lectins from genus Aplysina

Only a few animal phyla have been screened for the presence and distribution of lectins. Probably the most intensively studied group is the mollusk. In this investigation, 22 species from 12 families of tropical sponges collected in Los Roques National Park (Venezuela) were screened for the presence of lectins. Nine saline extracts exhibited strong hemagglutinating activity against pronase-treated hamster red blood cells; five of these reacted against rabbit red blood cells, four with trypsin-treated bovine red blood cells, and five with human red blood cells regardless of the blood group type. Extracts from the three species studied from genus Aplysina (archeri, lawnosa, and cauliformis) were highly reactive and panagglutinating against the panel of red blood cells tested. The lectins from A. archeri and A. lawnosa were purified to homogeneity by ammonium sulfate fractionation, affinity chromatography on p-aminobenzyl-beta-1-thiogalactopyranoside-agarose, and gel filtration chromatography. Both lectins exhibited a native molecular mass of 63 kDa and by SDS-polyacrylamide gel electrophoresis under reducing conditions have an apparent molecular mass of 16 kDa, thus suggesting they occur as homotetramers. The purified lectins contain 3-4 mol of divalent cation per molecule, which are essential for their biological activity. Hapten inhibition of hemagglutination was carried out to define the sugar binding specificity of the purified A. archeri lectin. The results indicate a preference of the lectin for nonreducing beta-linked d-Gal residues being the best inhibitors of red blood cells binding methyl-beta-d-Gal and thiodigalactoside (Gal beta 1-4-thiogalactopyranoside). The behavior of several glycans on immobilized lectin affinity chromatography confirmed and extended the specificity data obtained by hapten inhibition.

Tumor necrosis factor-alpha activation of NF-kappa B requires the phosphorylation of Ser-471 in the transactivation domain of c-Rel

Activation of the transcription factor NF-kappaB is controlled at two levels in resting T cells: an initial activation induced by the triggering of the TcR.CD3 complex and a second phase controlled by paracrine- or autocrine-secreted TNFalpha. The initial phase is regulated by p65 (RelA), whereas the second one is mainly dependent on c-Rel. We describe here a mutant clone, D6, derived from the parental T lymphoblastic line Jurkat that fails to activate NF-kappaB upon TNFalpha stimulation. This clone had no alteration in tumor necrosis factor-alpha (TNFalpha) signaling pathways nor in IkappaBalpha, -beta, or -epsilon expression and degradation. However, TNFalpha induced an exacerbated apoptotic response in this clone compared with Jurkat cells. This mutant clone showed a defect in the intermediate-late translocation of c-Rel to the nucleus promoted by TNFalpha stimulation, whereas early translocation is not affected. Activation or translocation of p65-containing complexes was not altered in this mutant clone. Sequencing of the c-Rel gene from this clone revealed a mutation of Ser-471 to Asn in the transactivation domain. The mutant S471N transactivation domain fused to the Gal4 DNA binding domain could not be activated by TNFalpha, unlike the wild type. Moreover, the overexpression of the mutant protein c-Rel S471N into Jurkat cells abolished TNFalpha-induced NF-kappaB activity, thus demonstrating that this mutation is responsible for the failure of TNFalpha stimulation of NF-kappaB. Moreover, extracts from TNFalpha-stimulated Jurkat cells phosphorylated in vitro recombinant wild type GST-c-Rel 464-481 but not the GST-c-Rel mutant. Thus, TNFalpha-induced phosphorylation of Ser-471 seems to be absolutely necessary for TNFalpha activation of c-Rel.

An essential role of the nuclear factor of activated T cells in the regulation of the expression of the cyclooxygenase-2 gene in human T lymphocytes

We have previously reported that transcriptional induction of cyclooxygenase-2 (COX-2) isoenzyme occurs early after T cell receptor triggering, suggesting functional implications of cyclooxygenase activity in this process. Here, we identify the cis-acting elements responsible for the transcriptional activation of this gene in human T lymphocytes. COX-2 promoter activity was induced upon T cell activation both in primary resting T lymphocytes and in Jurkat cells. This induction was abrogated by inhibition of calcineurin phosphatase with the immunosuppressive drug cyclosporin A, whereas expression of an active calcineurin catalytic subunit enhanced COX-2 transcriptional activation. Moreover, cotransfection of nuclear factor of activated T cells (NFAT) wild type protein transactivated COX-2 promoter activity. Conversely, dominant negative mutants of NFATc or c-Jun proteins inhibited COX-2 induction. Electrophoretic mobility shift assays and site-directed mutagenesis allowed the identification of two regions of DNA located in the positions -117 and -58 relative to the transcriptional start site that serves as NFAT recognition sequences. These results emphasize the central role that the Ca(2+)/calcineurin pathway plays in COX-2 transcriptional regulation in T lymphocytes pointing to NFAT/activator protein-1 transcription factors as essential for COX-2 promoter regulation in these cells.

Dexamethasone induces lipocalin-type prostaglandin D synthase gene expression in mouse neuronal cells

Lipocalin-type prostaglandin (PG) D synthase (L-PGDS) is responsible for the production of PGD(2), the main PG in the CNS. PGD(2) is an endogenous sleep inducer, and it is involved in the control of odor and pain responses and body temperature. In addition, PGD synthase transports lipophilic molecules in the subarachnoid space and CSF. By northern and western assays we show that the synthetic glucocorticoid dexamethasone, an inhibitor of PG production in most tissues, induces L-PGDS mRNA and protein in a dose- and time-dependent fashion in mouse neuronal GT1-7 cells. Accordingly, dexamethasone increases cellular L-PGDS enzymatic activity. Dexamethasone induced L-PGDS gene transcription in run-on assays and activated the mouse L-PGDS gene promoter in transiently transfected cells. It is interesting that the tumor promoter 12-O-tetradecanoyl-phorbol 13-acetate (TPA), which induces the synthesis of PGs in many tissues, inhibited the increase in L-PGDS expression induced by dexamethasone. In contrast, neither dexamethasone nor TPA affected the expression of cyclooxygenases-1 and -2. Our data demonstrate that dexamethasone induces L-PGDS gene transcription in neuronal cells.

Nitric oxide-producing CD11b(+)Ly-6G(Gr-1)(+)CD31(ER-MP12)(+) cells in the spleen of cyclophosphamide-treated mice: implications for T-cell responses in immunosuppressed mice

During recovery from intensive chemotherapy with cyclophosphamide (CTX), mice suffer a severe but transitory impairment in spleen cell proliferation to T-cell mitogens (Con A or anti-CD3 plus IL-2). Although CTX treatment reduced spleen T-cell cellularity, this cannot fully account for T-cell unresponsiveness. The results showed that CTX induces the colonization of spleen by an immature myeloid CD11b(+)Ly-6G(+)CD31(+) population. Its presence closely correlated with the maximum inhibition of T-cell proliferation. Moreover, this suppressive activity was dependent on nitric oxide (NO) production in cultures since (1) higher amounts of nitric oxide and inducible nitric oxide synthase (iNOS) mRNA were produced in CTX spleen cells (CTX-SC) than in control splenocyte cultures and (2) NOS inhibitors greatly improved the proliferation of T lymphocytes. Nitric oxide production and suppressive activity were also dependent on endogenous interferon-gamma (IFN-gamma) production since anti-IFN-gamma abrogated both effects. Finally, iNOS protein expression was restricted to a heterogeneous population of CD31(+) cells in which CD11b(+)Ly-6G(+) cells were required to suppress T-cell proliferation. These results indicated that CTX might also cause immunosuppression by a mechanism involving the presence of immature myeloid cells with suppressor activity. This may have implications in clinical praxis since inappropriate immunotherapies in patients treated with intensive chemotherapy could lead to deleterious T-cell responses. (Blood. 2000;95:212-220)

Frequency and pattern of p53 gene mutation in a cohort of Spanish women with node-negative breast cancer

Ethnic, racial and regional differences in the frequency and pattern of p53 gene mutations have been well documented. Some of these differences have been shown to have an impact on the survival of patients with breast cancer. In this study we explored the frequency and pattern of p53 abnormality in a cohort of Spanish women with node-negative breast cancer using PCR, subcloning and DNA sequencing of archival tumors. One hundred and seventy-eight cases of breast cancer diagnosed between 1981 and 1986 at the University of Oviedo Hospital in Oviedo, Spain were subjects of this study. Sequence analysis of exons 5 through 8 of p53 was performed on subcloned PCR-amplified DNA, extracted from formalin-fixed, paraffin-embedded tumors. Appropriate positive, negative, PCR, and polymerase controls were utilized and evaluated. Duplicate samples of the genomic DNA were re-evaluated on all cases showing more than one mutation. One hundred and five out of 178 breast cases (59%) carried one or more p53 gene mutations. Mutations were distributed randomly from codon 128 to 305. There were 123 (88%) transition, 10 (7%) transversion, 5 (3.5%) splice junction mutations, and 2 (1.5%) deletions. Eighty-three cases (61.5%) had missense mutation, 45 (33.5%) silent, 5 (3.5%) nonsense and 2 (1.5%) frameshifts. Eighty (75%) of 120 transitions were G:C to A:T, 11 (25%) of which occurred at CpG sites. Sixteen mutations were in novel codons not reported in breast cancers previously. Codons with the highest frequency of mutations in this group were 278, 273, 213 and 227. We also detected 27 tumors with more than one mutation within a single exon or in different exons in the same patient. These findings suggest that the frequency and pattern of p53 mutations in this group of Spanish women with breast cancer is different than those reported in the United States and Northern Europe.

HIV-1 infection induces differentiation of immature neural cells through autocrine tumor necrosis factor and nitric oxide production

Immature neural cell lines could be productively infected by HIV-1. Interestingly, this infection was associated with a differentiation to a mature neuronal phenotype, characterized by the expression of mature neurofilaments and cell adhesion molecules, intercellular cell adhesion molecule-1, and vascular cell adhesion molecule-1. Infection also induced TNF-alpha and IL-1beta mRNA expression, as well as the synthesis of inducible nitric oxide synthase by neuroblastoma cells. Exogenous addition of TNF-alpha, but not of IL-1beta or many other cytokines, including nerve growth factor, mimicked those effects induced by infection. Moreover, blocking endogenous TNF-alpha or NO production in cultures of infected cells with a neutralizing anti-TNF-alpha antibody or inducible nitric oxide synthase inhibitors prevented the expression of the mature cell phenotype as well as expression of intercellular cell adhesion molecule-1 and vascular cell adhesion molecule-1. Addition of NO generators and TNF-alpha activated NF-kappaB- and intercellular cell adhesion molecule-1-dependent promoter transcription, whereas inducible nitric oxide synthase inhibitors prevented the transcriptional activation of intercellular cell adhesion molecule-1 promoter that was induced by TNF-alpha. Those results suggest that HIV can infect immature neural cells and this infection induces their neural development via a TNF-alpha- and NO-mediated mechanism.

Induction of cyclooxygenase-2 on activated T lymphocytes: regulation of T cell activation by cyclooxygenase-2 inhibitors

Cyclooxygenase (COX), known to exist in two isoforms, COX-1 and COX-2, is a key enzyme in prostaglandin synthesis and the target for most nonsteroidal anti-inflammatory drugs. In this study, we show that human T lymphocytes express the COX-2 isoenzyme. COX-2 mRNA and protein were induced in both Jurkat and purified T cells stimulated by TCR/CD3 or PMA activation. COX-2 mRNA was induced very early after activation and superinduced by protein synthesis inhibitors, whereas it was inhibited by the immunosuppressive drug cyclosporin A, identifying it as an early T cell activation gene. Interestingly, treatment with COX-2-specific inhibitors such as NS398 or Celecoxib severely diminished early and late events of T cell activation, including CD25 and CD71 cell surface expression, IL-2, TNF-alpha, and IFN-gamma production and cell proliferation, but not the expression of CD69, an immediate early gene. COX-2 inhibitors also abolished induced transcription of reporter genes driven by IL-2 and TNF-alpha promoters. Moreover, induced transcription from NF-kappaB- and NF-AT-dependent enhancers was also inhibited. These results may have important implications in anti-inflammatory therapy and open a new field on COX-2-selective nonsteroidal anti-inflammatory drugs as modulators of the immune activation.

Cloning and characterization of Rab and Ran/TC4 cDNA clones in Trichinella spp

The cloning and characterization of seven Rab and three Ran/TC4 partial cDNA sequences in both cystic (Trichinella spiralis and T. britovi) and noncystic species (T. pseudospiralis) are reported. These molecules were cloned by rapid amplification of cDNA ends via polymerase chain reaction (RACE-PCR), using cDNA from the aforementioned Trichinella spp. coupled to the AP1 adaptor. As primers, AP1 and 5B (derived from the WDTAGQE sequence of region 2 specific for Rab and Ran proteins) sequences were included in the PCR. The cloned cDNAs were sequenced and characterized by both Southern-blot and Northern-blot analysis. Trichinella spp. Rab- and Ran-like molecules showed divergences in both the nucleotide and the deduced amino acid sequences as compared with the corresponding homologues previously described in other organisms. In addition, differences were observed among the Trichinella species, mainly between the cystic and the noncystic species, in both DNA restriction-enzyme polymorphism and expression of the six GTPases isolated.

Inhibitory effects of the Trypanosoma cruzi membrane glycoprotein AGC10 on the expression of IL-2 receptor chains and secretion of cytokines by subpopulations of activated human T lymphocytes

The Trypanosoma cruzi membrane glycoprotein AGC10 has been shown to alter some human macrophage functions (De Diego, J. L. et al., J. Immunol. 1997. 159: 4983-4989). We show here that, in the presence of AGC10, [3H]thymidine incorporation by normal human lymphocytes stimulated with anti-CD3 or phytohemagglutinin (PHA) is severely curtailed. This effect was found to involve down-regulation of the expression of both CD25 (IL-2R alpha) and CD122 (IL-2R beta) on the lymphocyte membrane and a marked decrease in the level of up-regulation of the expression of surface CD132 (IL-2R gamma or gamma(c)). These alterations occurred in fairly large proportions of CD4+ and CD8+ lymphocytes. AGC10 also inhibited proliferation and expression of IL-2 receptor chains by activated T lymphocytes virtually depleted of monocytes/macrophages, indicating that these effects do not necessarily require prior modification of monocyte/macrophage function by AGC10. Human lymphocytes stimulated with anti-CD3 or PHA also displayed a markedly decreased capacity to secrete IL-2 and IFN-gamma, suggesting that AGC10 affected at least Th1 cell functions. Cell viability in cultures containing or lacking AGC10 was comparable over a 72-h period, and neither CD25 expression by, nor the viability of, PHA-stimulated Jurkat cells was altered by AGC10, ruling out that the effects of AGC10 are due to cell killing. These results highlight down-regulatory effects on activated T lymphocytes exerted by a membrane molecule from a parasite causing a disease whose acute phase is accompanied by immunosuppression.