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Biomedical subjects

N Trede

Publications and source records attributed to N Trede.

8 recordsLinked to original sources

Superantigens activate HIV-1 gene expression in monocytic cells.

Binding of superantigens to MHC class II molecules results in transduction of biochemical signals leading to cellular activation and gene expression. We demonstrate that the staphylococcal superantigens toxic shock syndrome toxin-1 (TSST-1) and staphylococcal enterotoxin A (SEA) activate HIV-1-LTR-driven transcription of chloramphenicol acetyl transferase in the human monocytic cell line THP-1. Induction of HIV-1-LTR-driven transcription in THP-1 cells by superantigens was associated with the induction of nuclear factor-kappa B DNA-binding activity. Superantigens also increased viral protein secretion from the granulocyte-macrophage colony-stimulating factor-pretreated chronically infected human monocytic cell line U1. Induction of HIV-1 gene expression in monocytic cells by superantigens occurred via tumor necrosis factor-alpha-dependent and -independent mechanisms. Our results suggest that superantigens and other MHC class II ligands may activate HIV-1 gene expression in monocytes/macrophages.

Base Sequence↗

Role of protein tyrosine phosphorylation in monokine induction by the staphylococcal superantigen toxic shock syndrome toxin-1.

The staphylococcal superantigen toxic shock syndrome toxin-1 (TSST-1) is a potent inducer of IL-1 beta and TNF-alpha synthesis in human monocytes. As superantigens are high affinity ligands for MHC class II molecules, the induction of monokines by TSST-1 provides a biologically relevant model of MHC class II-mediated transmembrane signaling. In this study, we show that TSST-1 induces cytoplasmic protein tyrosine phosphorylation in the human monocytic cell line THP-1. This induction was greatly enhanced by cross-linking TSST-1 with biotin-avidin. The functional relevance of tyrosine phosphorylation induced by TSST-1 was demonstrated by the finding that three specific inhibitors of protein tyrosine kinases strongly inhibited the induction of IL-1 beta mRNA by TSST-1. These data suggest that protein tyrosine kinase activation plays a critical role in MHC class II-mediated transmembrane signalling by staphylococcal superantigens.

Antigens, Bacterial↗

Complexity, polymorphism, and recombination of mouse T-cell receptor alpha gene families.

Genomic DNA from a large panel of inbred strains of mice were hybridized sequentially with 15 V alpha, 2 V delta, 1 C alpha, and 1 C delta probes. Most of the V alpha probes detected a high degree of polymorphism and have allowed the definition of five mouse T-cell receptor alpha (Tcr alpha) haplotypes. One of these haplotypes (Tcre alpha) appears to arise from a recombination between the Tcrb alpha and Tcra alpha haplotypes, the latter being the most frequently found in the conventional inbred strains. This recombination event clearly indicates that the members of at least 11 V alpha sub-families are not closely linked but highly interspersed with one another on chromosome 14.

Animals↗

Serological screening for allergy to inhalants by multi-allergen-radioimmunoassay.

201 children with inhalant allergy were examined with a new serological screening test ("Multi-Allergen-Test"). The sensitivity (95.1%) and specificity (91.9%) of the test were determined by comparing it to a "clinical classification", including results of history, physical examination, skin test and investigation for specific IgE antibodies. This yielded a diagnostic efficiency of 93.5%. A subsequent comparison of these results with the classification of patients by age-related total IgE levels showed the superiority of the "Multi-Allergen-Test" as far as screening for inhalant allergies is concerned. Additionally, the results for the specificity of the test were reproduced by examining another 18 children with food allergy, who had elevated total IgE levels but no inhalant allergic symptoms. The "Multi-Allergen-Test" proved to be a suitable screening procedure for inhalant allergy.

Allergens↗