Modulation of the cell-mediated immune function by interferon α, β or γ can partially reverse the immunosuppression induced by human T-cell leukemia virus I in human cord blood cultures

Summary Infection with human T-cell leukemia virus type I (HTLV-I) is associated in vitro and in vivo with a remarkable depression of cell-mediated immune functions. In the present report it is shown that early events following virus-induced suppression of the cell-mediated immune response of freshly isolated cord blood mononuclear cells (CBL) infected with HTLV-I can be partially counteracted by treatment with interferons , or (IFN). All three types of IFN exerted a protective effect on CBL cultures exposed to the virus. This resulted in: (a) a reduced number of virus-positive cells until 4 weeks of culture; (b) delay in the clonal expansion of infected cells (IFN and ); (c) increased natural killer cell activity of CBL, 1 week post-infection (p.i.), mediated by IFN; (d) increase of allospecific recognition of infecting and priming HTLV-I donor MT-2 cells by CBL in a cytotoxic-T-lymphocyte-like response, mediated by IFN and particularly by IFN; (e) phenotype distribution of CBL subpopulations, tested 4 days p.i., more similar to that of non-infected CBL cultures.In contrast, the overall CBL proliferation, that is profoundly depressed during the first week p.i., was not restored by IFN treatments, suggesting that boosting of the cell-mediated killing induced by IFN might involve the maturation of undifferentiated precursor cells rather than stimulation of their proliferation. The improvement of the efficiency of the antiviral immune response induced by treatment with IFN is likely to contribute to the clearance of virus-positive cells during the early phase of infection. This would provide experimental evidence to support an immunopharmacological approach contributing to the conversion of HTLV-I carriers from positive to negative.     

The mitochondrial tricarboxylate carrier of silver eel: chemical modification by sulfhydryl reagents

The tricarboxylate (or citrate) carrier was purified from eel liver mitochondria and functionally reconstituted into liposomes. Incubation of the proteoliposomes with various sulfhydryl reagents led to inhibition of the reconstituted citrate transport activity. Preincubation of the proteoliposomes with reversible SH reagents, such as mercurials and methanethiosulfonates, protected the eel liver tricarboxylate carrier against inactivation by the irreversible reagent N-(1-pyrenyl)maleimide (PM). Citrate and L-malate, two substrates of the tricarboxylate carrier, protected the protein against inactivation by sulfhydryl reagents and decreased the fluorescent PM bound to the purified protein. These results suggest that the eel liver tricarboxylate carrier requires a single population of free cysteine(s) in order to manifest catalytic activity. The reactive cysteine(s) is most probably located at or near the substrate binding site of the carrier protein.     

Antibody Complementarity-Determining Regions (CDRs): A Bridge between Adaptive and Innate Immunity

Background

It has been documented that, independently from the specificity of the native antibody (Ab) for a given antigen (Ag), complementarity determining regions (CDR)-related peptides may display differential antimicrobial, antiviral and antitumor activities.

Methodology/Principal Findings

In this study we demonstrate that a synthetic peptide with sequence identical to V_HCDR3 of a mouse monoclonal Ab (mAb) specific for difucosyl human blood group A is easily taken up by macrophages with subsequent stimulation of: i) proinflammatory cytokine production; ii) PI3K-Akt pathway and iii) TLR-4 expression. Significantly, V_HCDR3 exerts therapeutic effect against systemic candidiasis without possessing direct candidacidal properties.

Conclusions/Significance

These results open a new scenario about the possibility that, beyond the half life of immunoglobulins, Ab fragments may effectively influence the antiinfective cellular immune response in a way reminiscent of regulatory peptides of innate immunity.     

Defective activation of c-Src in cystic fibrosis airway epithelial cells results in loss of tumor necrosis factor-alpha-induced gap junction regulation

Tumor necrosis factor-alpha (TNF-alpha) signaling is central to the transmission of the innate immune response and subsequent activation of the adaptive immune system. The functioning of both systems is required for optimal clearance of pathogens from the airways. In cystic fibrosis (CF), dysfunction of the CF transmembrane conductance regulator (CFTR) is associated with recurrent pulmonary infections despite an intense inflammatory and immune response. We reported recently that TNF-alpha decreased gap junction connectivity in non-CF airway cells, a mechanism that was absent in CF cells expressing the DeltaPhe-508 mutant of CFTR. We have now identified the tyrosine kinase c-Src as a possible pathway between the mediators of inflammation and the gap junction protein connexin43 (Cx43). Indeed, TNF-alpha increased the proportion of activated c-Src in non-CF airway cells. Moreover, pharmacological antagonists and expression in non-CF cells of a dominant negative construct of c-Src prevented Cx43 channel closure by TNF-alpha. Finally, gap junction channel closure was prevented by expression of a Cx43 mutant lacking tyrosine phosphorylation sites for c-Src. Additional experiments showed that activation of c-Src was defective in CF airway cells but rescued in CFTR-corrected CF cells. These data suggest that CFTR dysfunction is associated with altered TNF-alpha signaling, resulting in the persistence of gap junction connectivity in CF airway cells. We propose that altered regulation of c-Src may contribute to the dysregulated inflammatory response that is characteristic of the CF phenotype.     

Gap Junctional Communication Does not Contribute to the Interaction Between Neutrophils and Airway Epithelial Cells

Cystic fibrosis (CF) is characterized by intense neutrophil migration into the airways. Increasing evidence indicates that interaction between neutrophils and airway epithelial cells contributes to the modulation of the inflammatory response. Blood neutrophils were reported to express connexins and form gap junctions with endothelial cells, thereby establishing gap junctional communication. We tested whether altered communication between human neutrophils and airway epithelial cells may contribute to the exaggerated inflammatory response observed in CF patients. Microinjections did not reveal dye coupling between activated blood neutrophils. By constrast, diffusion of calcein between neutrophils and airway epithelial cells of CF or non-CF origin was observed in transmigration and adhesion assays. This diffusion was prevented with probenicid, an inhibitor of ATP-dependent organic anion pumps, but not with gap junction blockers. Finally, RT-PCR failed to detect mRNAs for six connexins in blood neutrophils. These results suggest that gap junctional communication does not contribute to neutrophil-airway epithelial cell interaction.     

Gap junctional communication in tissue inflammation and repair

Local injury induces a complex orchestrated response to stimulate healing of injured tissues, cellular regeneration and phagocytosis. Practically, inflammation is defined as a defense process whereby fluid and white blood cells accumulate at a site of injury. The balance of cytokines, chemokines, and growth factors is likely to play a key role in regulating important cell functions such as migration, proliferation, and matrix synthesis during the process of inflammation. Hence, the initiation, maintenance, and resolution of innate responses depend upon cellular communication. A process similar to tissue repair and subsequent scarring is found in a variety of fibrotic diseases. This may occur in a single organ such as liver, kidneys, pancreas, lung, skin, and heart, but fibrosis may also have a more generalized distribution such as in atherosclerosis. The purpose of this review is to summarize recent advances on the contribution of gap junction-mediated intercellular communication in the modulation of the inflammatory response and tissue repair.     

The complete genome sequence of the meat-borne lactic acid bacterium Lactobacillus sakei 23K

Lactobacillus sakei is a psychotrophic lactic acid bacterium found naturally on fresh meat and fish. This microorganism is widely used in the manufacture of fermented meats and has biotechnological potential in biopreservation and food safety. We have explored the 1,884,661-base-pair (bp) circular chromosome of strain 23K encoding 1,883 predicted genes. Genome sequencing revealed a specialized metabolic repertoire, including purine nucleoside scavenging that may contribute to an ability to successfully compete on raw meat products. Many genes appear responsible for robustness during the rigors of food processing--particularly resilience against changing redox and oxygen levels. Genes potentially responsible for biofilm formation and cellular aggregation that may assist the organism to colonize meat surfaces were also identified. This genome project is an initial step for investigating new biotechnological approaches to meat and fish processing and for exploring fundamental aspects of bacterial adaptation to these specific environments.     

Meiotic studies of a 38,XY/39,XXY mosaic boar

Klinefelter's syndrome (KS) is the most common sex chromosome abnormality identified in human males. This syndrome is generally associated with infertility. Men with KS may have a 47,XXY or a 46,XY/47,XXY karyotype. Studies carried out in humans and mice suggest that only XY cells are able to enter and complete meiosis. These cells could originate from the XY cells present in mosaic patients or from XXY cells that have lost one X chromosome. In pig, only 3 cases of pure 39,XXY have been reported until now, and no meiotic analysis was carried out. For the first time in pig species we report the analysis of a 38,XY/39,XXY boar and describe the origin of the supplementary X chromosome and the chromosomal constitutions of the germ and Sertoli cells.     

From <Emphasis Type="Italic">Pichia anomala</Emphasis> killer toxin through killer antibodies to killer peptides for a comprehensive anti-infective strategy

“Antibiobodies”, antibodies (Abs) with antibiotic activity, internal image of a Pichia anomala killer toxin (PaKT) characterized by microbicidal activity against microorganisms expressing β-glucans cell-wall receptors (PaKTRs), were produced by idiotypic vaccination with a PaKT-neutralizing monoclonal Ab (PaKT-like Abs) or induced by a protein-conjugated β-glucan. Human natural PaKT-like Abs (PaKTAbs) were found in the vaginal fluid of women infected with KT-sensitive microorganisms. Monoclonal and recombinant PaKT-like Abs, and PaKTAbs proved to be protective against experimental candidiasis, cryptococcosis and aspergillosis. A killer decapeptide (KP), synthesized from the sequence of a recombinant PaKT-like Ab or produced in transgenic plants, showed a microbicidal activity in vitro, neutralized by β-glucans, a therapeutic effect in vivo, against experimental mucosal and systemic mycoses, and a prophylactic role in planta, against phytopathogenic microorganisms, respectively. KP showed fungicidal properties against all the defective mutants of a Saccharomyces cerevisiae library, inclusive of strains recognized to be resistant to conventional antifungal drugs. KP inhibited in vitro, ex vivo and/or in vivo HIV-1 and Influenza A virus replication, owing to down-regulation of CCR5 co-receptors, physical block of the gp120-receptor interaction and reduction in the synthesis of glycoproteins, HA and M1 in particular. KP modulated the expression of costimulatory and MHC molecules on murine dendritic cells, improving their capacity to induce lymphocyte proliferation. KP, proven to be devoid of cytotoxicity on human cells, showed self-assembly-releasing hydrogel-like properties, catalyzed by β 1,3 glucan. PaKT’s biotechnological derivatives may represent the prototypes of novel antifungal vaccines and anti-infective drugs characterized by different mechanisms of action.     

A soft tissue artefact model driven by proximal and distal joint kinematics

When analysing human movement through stereophotogrammetry, skin-markers are used. Their movement relative to the underlying bone is known as a soft tissue artefact (STA). A mathematical model to estimate subject- and marker-specific STAs generated during a given motor task, is required for both skeletal kinematic estimators and comparative assessment using simulation. This study devises and assesses such a mathematical model using the paradigmatic case of thigh STAs. The model was based on two hypotheses: (1) that the artefact mostly depends on skin sliding, and thus on the angles of hip and knee; (2) that the relevant relationship is linear. These hypotheses were tested using data obtained from passive hip and knee movements in non-obese specimens and from running volunteers endowed with both skin- and pin-markers.