Synthetic peptides mapping to epitopes of the extracellular domain of the interleukin-2 receptor β-chain to inhibit T-cell activation

Expression of the high-affinity IL-2 receptor (IL-2R) on the surface of activated T cells makes it an attractive target for selective inhibition of alloreactive T cells in organ transplantation. IL-2 binds to its receptor via the extracellular domain of the β-chain. In this study we synthesized synthetic peptides that map to epitopes of this domain and tested their ability to inhibit the activation and proliferation of mitogen-stimulated peripheral-blood T cells. Solid-phase synthesis was applied to create three oligopeptides of primary structures corresponding to the epitopes M¹⁰⁷-E¹¹⁸, Y¹⁷⁸-Q¹⁹⁹, and E¹⁹⁰-Q¹⁹⁹ of the extracellular domain of the IL-2Rβ-chain. A nonhomologous peptide served as control. Peripheral-blood mononuclear cells isolated from 16 healthy volunteers (median age 41 years, range 26 to 56 years) were cultured with various concentrations of peptides and the mitogen phytohemagglutinin (PHA). The inhibitory effect of the peptides on cell proliferation was evaluated by automated cell counting and colorimetric proliferation assays. Cell activation was assessed by immunophenotyping using antibodies directed toward CD4, CD25, or CD69. The amount of IL-2 in culture supernates was measured by enzyme-linked immunoassay. Cultures in the presence of the peptide M¹⁰⁷-E¹¹⁸ (500 nmol/L) inhibited PHA-induced T-cell proliferation by 38%, and IL-2 secretion by 57%. Immunophenotyping confirmed suppression of activated T cells. Peptides Y¹⁷⁸-Q¹⁹⁹ and E¹⁹⁰-Q¹⁹⁹ inhibited proliferation, but failed to significantly affect IL-2 secretion. The control peptide showed no effect on the activation parameters. Our data indicate that the M¹⁰⁷-E¹¹⁸ peptide has promise for organ transplantation therapy.     

Cytokine production and monocyte HLA-DR expression as predictors of outcome for patients with community-acquired severe infections

This study was performed to evaluate the impact of pro- and anti-inflammatory molecules and human leukocyte antigen DR (HLA-DR) expression as markers of immune status for the final outcome of septic patients. The study included 30 patients with severe sepsis due to community-acquired infections. Concentrations of tumor necrosis factor alpha (TNF-alpha), interleukin-6 (IL-6), IL-8, IL-10, and transforming growth factor beta1 (TGF-beta1) in serum, as well as monocyte HLA-DR expression, were determined on admission and on days 3, 10, 13, and 17 during hospitalization. Of the 30 patients enrolled, 13 survived, while 17 died during their hospital stay. All patients had significantly lower HLA-DR expression and higher pro- and anti-inflammatory cytokine levels than healthy individuals. HLA-DR expression was significantly decreased in nonsurvivors at almost all time points. In nonsurvivors, higher levels in serum of TNF-alpha on days 13 and 17; IL-6 levels on day 3; and IL-10 on days 3, 10, and 13 were found. Baseline levels of TGF-beta1 were significantly higher in survivors. Independent risk factors of mortality were IL-10 levels on days 3 and 10, while monocyte HLA-DR expression on admission was a good predictor for survival. Several pro- and anti-inflammatory cytokines are oversynthesized during severe infections, especially in patients with a poor outcome. Monocyte HLA-DR expression is an early and constant predictive marker for survival in severe sepsis, while serum IL-10 levels on days 3 and 10 have negative prognostic value for the final outcome.     

Type 1 and type 2 cytokine-producing CD4+ and CD8+ T cells in primary antiphospholipid syndrome

Antiphospholipid syndrome (APS) is an autoimmune condition characterized by thrombosis and/or recurrent fetal loss as well as the presence of autoantibodies against epitopes present on phospholipid-binding proteins. The role of cellular immunity in the pathogenesis of the syndrome remains unclear. We studied the cellular phenotype and the production of type 1 [interferon (IFN)-, interleukin (IL)-2] and type 2 (IL-4, IL-10) cytokines by CD4+ and CD8+ T-lymphocyte subsets in 13 patients with untreated primary APS (PAPS) and in 32 healthy controls. The production of cytokines was determined in T cells after a 5-h culture with or without mitogenic stimulation using a flow cytometric method of intracellular cytokine staining. In six of the patients these studies were repeated 6 months later. In PAPS patients we found a reduced percentage of circulating CD4+CD45RA+ and an increased percentage and absolute number of CD8+HLA-DR+ cells. A type 1 response was observed in the patients unstimulated cells, indicated by an increase in IFN--producing CD8+, IL-2-producing CD4+ T cells, and a decrease in IL-4-producing CD4+ and CD8+ T cells. Similar results were obtained in the patients at follow-up. Taken together, these results suggest a chronic in vivo stimulation of CD4+ and CD8+ T cells in PAPS patients exhibiting a type 1 polarization. Changes of cellular immunity may contribute to the pathogenesis of the clinical manifestations of the syndrome and might be proven to be useful targets for therapeutic interventions in the future.     

Polyclonal hypergammaglobulinemia in a case of B-cell chronic lymphocytic leukaemia: the result of IL-2 production by the proliferating monoclonal B cells?

Summary. CLL is typically characterized by acquired hypogammaglobulinemia. We report the case of a female patient suffering from B-CLL who developed polyclonal hypergammaglobulinaemia: 38-3 g/I polyclonal IgG, 0.97g/1 IgA and 0.33 g/1 IgM. Immunophenotyping showed a monoclonal lymphocytic population CD19⁺ CD5⁺ CD40⁺ CD23+, low slg⁺ (95%), K type in the great majority (96%). RT-PCR of immunoglobulin genes gave evidence of monoclonal rearrangement of the IgM type. Our tests showed that IL-2 was produced when leukaemic B cells were stimulated with phorbol myristate acetate, ionomycin and lipopoly-saccharide. In addition, transfections with the full IL-2 promoter or elements thereof revealed that IL-2 expression is inducible and mediated through the NF-kB-promoter element. Finally, the amount of IL-2 secreted by these cells is about 39ng/ml/10⁶ cells, which is remarkably high for non-T cells. These results suggest that the large amounts of polyclonal IgG seen in this case of B-CLL are secreted by normal B cells which are in turn stimulated by IL-2 produced by proliferating monoclonal (leukaemic) B cells. Under cyclosporin A treatment, immunoglobulin secretion and B cell count remained low.     

Language development and emergent literacy in preschool

To promote school readiness, preschool and Head Start teachers are incorporating more emergent literacy activities into their curriculum. This article argues that emergent literacy is subordinate to oral language development, rather than language development being subordinate to emergent literacy. Literature on components of emergent literacy is reviewed and a framework for a preschool curriculum that promotes oral language development and emergent literacy is presented. The article concludes with the recommendation that phonologic sensitivity and letter knowledge be taught in developmentally appropriate ways within the context of a language-rich preschool environment that specifically targets vocabulary enrichment.     

Oxaliplatin-induced acute-onset thrombocytopenia, hemorrhage and hemolysis

BACKGROUND: Oxaliplatin is a novel platinum derivative with established anti-tumor activity in colorectal cancer. Acute-onset hemolytic anemia and thrombocytopenia associated with this drug have rarely been reported and some of these cases have been severe or even fatal. CASE REPORT: This case report describes a patient who developed fever, chills, abdominal and back pain as well as sudden-onset severe thrombocytopenia, upper gastrointestinal bleeding and hemolysis immediately after treatment with oxaliplatin for metastatic colorectal cancer. The reaction appeared during the 14th cycle of chemotherapy. Corticosteroids and antihistamines were administered together with platelet transfusions. Over the next 2 days platelet count improved and the syndrome abated. The patient was discharged 4 days later. Furthermore, the reaction was accompanied by a strongly positive Coombs test and increased TNF-alpha and IL-10 serum levels which returned to normal following anti-inflammatory drug administration. CONCLUSION: Physicians should be aware of the possibility of acute hematological emergencies following oxaliplatin administration.     

Antagonistic effects of human cyclic MBP(87-99) altered peptide ligands in experimental allergic encephalomyelitis and human T-cell proliferation.

The immunodominant myelin basic protein (MBP) peptide comprising residues 87-99 is a self-antigen in multiple sclerosis (MS). In Lewis rats this epitope induces experimental allergic encephalomyelitis (EAE), a demyelinating disease of the central nervous system, and is a model of MS. Structure-activity studies have shown that Lys(91) and Pro(96) residues are important for encephalitogenicity. Replacement of Lys and/or Pro residues with Arg and/or Ala, respectively, results in suppression of EAE. A potent linear altered peptide ligand of the immunodominant sequence MBP(83-99) has been selected for clinical trial (Nat. Med. 2000, 6, 1167, 1176). In the present report, two cyclic analogues, cyclo(91-99)[Ala(96)]MBP(87-99) and cyclo(87-99)[Arg(91), Ala(96)]MBP(87-99) were designed by NMR and molecular modeling data on human MBP(87-99) epitope (Val(87)-His-Phe-Phe-Lys-Asn-Ile-Val-Thr-Pro-Arg-Thr-Pro(99)) and its linear antagonist peptide analogue [Arg(91), Ala(96)]MBP(87-99). These analogues (altered peptide ligands) inhibited EAE in Lewis rats and decreased inflammation in the spinal cord. In addition, the analogue cyclo(87-99)[Arg(91), Ala(96)]MBP(87-99) induced proliferation of human peripheral blood T-cells. These cyclic MBP(87-99) peptide analogues may lead to the design of potent antagonist mimetics for treating MS.