Cell Cytokine Production Profiles Research Articles

A Novel α/β Hydrolase Domain Protein Derived From Haemonchus contortus Acts at the Parasite-Host Interface.

The α/β-hydrolase domain (ABHD) proteins belonging to α/β-hydrolase (ABH) superfamily are ubiquitously distributed throughout all the organisms, and their functional roles have been implicated in energy metabolism, cell signaling, growth and development. In our preliminary work, we identified a novel ABHD protein derived from Haemonchus contortus excretory-secretory (ES) proteins (HcESPs) that interacted with host T cells. Here, we demonstrated that H. contortus ABHD (HcABHD) protein, expressed in all life-cycle stages of H. contortus, is a mammalian ABHD17 homolog with immunodiagnostic utility and lipase activity. Given its catalytic activities and immunomodulatory potentials, we further investigated the functional diversity of HcABHD as an individual ES protein in parasite-host interactions. HcABHD protein may serve as depalmitoylase or thioesterase to suppress cell viability, inhibit cell proliferation, induce intrinsic and extrinsic T cell apoptosis, and cause cell cycle arrested at G1 phase. Moreover, recombinant HcABHD stimuli exerted critical controls on T cell cytokine production profiles, predominantly by inhibiting the secretions of interleukin (IL)-4, interferon-gamma (IFN-γ) and transforming growth factor-beta (TGF-β) 1, and promoting IL-10 production. As the immunomodulator acting at the parasite-host interface, HcABHD protein may have potential applications for the vaccine development of therapeutic intervention. Together, these findings may help illuminate the molecular and particularly immunomodulatory aspects of ES proteins and contribute to an enhanced understanding of parasite immune evasion in H. contortus-host biology.

Proteomic analysis revealed T cell hyporesponsiveness induced by Haemonchus contortus excretory and secretory proteins

Haemonchus contortus has evolved highly integrated and sophisticated mechanisms to promote coexistence with hosts. The excretory-secretory (ES) products generated by this parasite contribute to the regulation of the host immune response to facilitate immune evasion and induce chronicity, but the proteins responsible for this process and the exact cellular mechanisms have yet to be defined. In this study, we identified 114 H. contortus ES proteins (HcESPs) interacting with host T cells and 15 T cell binding receptors via co-immunoprecipitation and shotgun liquid chromatography-tandem mass spectrometry analysis. Based on bioinformatics analysis, we demonstrated that HcESPs could inhibit T cell viability, induce cell apoptosis, suppress T cell proliferation and cause cell cycle arrest. Furthermore, the stimulation of HcESPs exerted critical control effects on T cell cytokine production profiles, predominantly promoting the secretion of interleukin (IL)-10, IL-17A and transforming growth factor-β1 and inhibiting IL-2, IL-4 and interferon-γ production. Collectively, these findings may provide insights into the interaction between ES proteins and key host effector cells, enhancing our understanding of the molecular mechanism underlying parasite immune evasion and providing new clues for novel vaccine development.

Interleukin 8 Level, Reticulocyte Counting and aPTT Ratio in Brazilian Sickle Cell Anemia Patients with Leg Ulcers

Abstract 4835 Background:Sickle cell anemia (SCA) is characterized by a chronic inflammatory state in which oxidative stress, particularly in the endothelium, exerts a strong influence on the pathogenesis of vaso-occlusion and may be implicated in patients' clinical heterogeneity and survival. It has been suggested that the cytokine production profile of cells involved in the immune response may vary among patients with SCA. Leg ulcers (LU) represent a severe complication in these patients, and this condition has been associated with specific end-organ damage and an increase in morbidity and mortality. Recent studies have shown that venous obstruction, endothelial dysfunction, coagulopathy and infections are implicated in the complex pathogenesis of LU. Aims:To determine IL-1β, IL-6 and IL-8 plasma levels and gene expression rates as well as hematological and coagulation parameters and correlate these with the history of LU in adult SCA patients followed up at HEMOPE, in the state of Pernambuco, northeastern Brazil. Methods:Peripheral blood samples from 92 patients (median age 27 years; 42 female; 52 male; all Afro-descendants) in the steady state who had been diagnosed with SCA (HbSS), had not received a transfusion and were not using hydroxyurea were analyzed. Plasma levels of cytokines were determined by ELISA, and the gene expression rates by qRT-PCR. The patients' clinical and laboratorial characteristics were obtained from their medical charts. Statistical analysis was performed using the SAS System for Windows version 9.2. Results:Median age was higher in patients with a history of LU than in those without a history (33.1 vs. 28.4; p = 0.04). Although no statistically significant (p = 0.5) differences in IL-8 gene expression rates were observed, IL-8 plasma levels were significantly higher in patients with a history of LU than in patients without a history (23.8 vs. 7.7; p = 0.01) (Figure 1). Thus, patients with high levels of IL-8 had an increased risk for the occurrence of leg ulcers (OR = 1.01; 95% CI = 1.00–1.02). The ROC curve showed that IL-8 levels higher than 8.55 pg/mL could indicate the presence of LU (accuracy = 71.6%; sensitivity = 73.7%; specificity = 68.5%). The laboratory tests revealed reticulocyte counts and activated partial thromboplastin time (aPTT) ratios (R) that were significantly higher in patients with a history of LU than in those without a history (11.8 vs. 8.4, p = 0.01; 1.1 vs. 0.9, p = 0.04, respectively). Both the higher reticulocyte counts and R values were associated with increased risk for the occurrence of leg ulcers in these patients (OR = 1.12, 95% CI = 1.02 – 1.20; OR = 24.28, 95% CI = 1.20 – 486.09, respectively). Conclusion:In this study, patients who had had LU at some time in their lives showed significantly higher IL-8 levels, reticulocyte counts and R values than patients who had never had LU. Our results therefore suggest a relationship between the parameters described above and LU in patients with SCA. These parameters could perhaps be used, in association with different genetic modulators that may contribute to different clinical phenotypes observed in this disease, as markers of this clinical manifestation of SCA or of a propensity to develop it. [Display omitted] Financial Support: CAPES (Brazil)/FAPESP/CNPq/INCTS Disclosures:No relevant conflicts of interest to declare.

Distinct methylation of the interferon gamma (IFN-gamma) and interleukin 3 (IL-3) genes in newly activated primary CD8+ T lymphocytes: regional IFN-gamma promoter demethylation and mRNA expression are heritable in CD44(high)CD8+ T cells.

Differential genomic DNA methylation has the potential to influence the development of T cell cytokine production profiles. Therefore, we have conducted a clonal analysis of interferon (IFN)-gamma and interleukin (IL)-3 gene methylation and messenger (m)RNA expression in primary CD8+ T cells during the early stages of activation, growth, and cytokine expression. Despite similar distributions and densities of CpG methylation sites, the IFN-gamma and IL-3 promoters exhibited differential demethylation in the same T cell clone, and heterogeneity between clones. Methylation patterns and mRNA levels were correlated for both genes, but demethylation of the IFN-gamma promoter was widespread across >300 basepairs in clones expressing high levels of IFN-gamma mRNA, whereas demethylation of the IL-3 promoter was confined to specific CpG sites in the same clones. Conversely, the majority of clones expressing low or undetectable levels of IFN-gamma mRNA exhibited symmetrical methylation of four to six of the IFN-gamma promoter CpG sites. Genomic DNA methylation also has the potential to influence the maintenance or stability of T cell cytokine production profiles. Therefore, we also tested the heritability of IFN-gamma gene methylation and mRNA expression in families of clones derived from resting CD44(low)CD8+ T cells or from previously activated CD44(high)CD8+ T cells. The patterns of IFN-gamma gene demethylation and mRNA expression were faithfully inherited in all clones derived from CD44(high) cells, but variable in clones derived from CD44(low) cells. Overall, these findings suggest that differential genomic DNA methylation, including differences among cytokine genes, among individual T cells, and among T cells with different activation histories, is an important feature of cytokine gene expression in primary T cells.

Characterization of ovomucoid‐specific T‐cell lines and clones from egg‐allergic subjects

In the pathogenesis of allergic reactions, T cells and cytokines play a major role. However, characterizations of food allergen-specific T cells are very limited. In this study, we screened the peripheral blood mononuclear cells (PBMC) of 14 patients for reactivity to ovomucoid (Gal d I), the major hen's egg allergen, and ovalbumin (Gal d II). Cell lines and clones specific to ovomucoid were generated from PBMC of four egg-allergic subjects, in order to study antigen domain specificity and cell cytokine production profiles. The results demonstrated, firstly, that egg-allergic patients respond to ovomucoid rather than to ovalbumin, and, secondly, that antigen specificity is predominantly directed toward the second and third domains of ovomucoid. The T-cell cytokine message was characterized by reverse transcriptase polymerase chain reaction (RT-PCR). Cell lines and clones from all four patients consistently expressed interleukin (IL)-5. IL-4, IL-13, and interferon-gamma were found to be expressed only by certain lines or clones. This observation suggests a central pathogenic role for IL-5 in food allergy-related symptoms.