Functional characterization of an antigen involved in an early step of T-cell activation

Proceedings of the National Academy of Sciences (Impact Factor: 9.67). 07/1987; 84(12):4205-9. DOI: 10.1073/pnas.84.12.4205
Source: PubMed


An activation antigen, identified by the monoclonal antibody MLR3, is described that is present on activated T lymphocytes and thymocytes but not on resting T lymphocytes. Immunoprecipitation of radiolabeled membranes from an activated T-cell line showed that the MLR3-binding molecule has a molecular size of 28-34 kDa. Immunofluorescence analysis showed that the appearance of the MLR3 antigen is an early event and precedes that of the interleukin 2 receptor both in T lymphocytes and thymocytes. The proliferative response of resting T cells to OKT3-Sepharose and interleukin 1 or accessory cells, but not the interleukin 2-dependent proliferation, was inhibited by the addition of MLR3 monoclonal antibodies. Similar results wer also obtained in an interleukin 1-dependent human thymocyte proliferation assay. In addition when MLR3-positive cells were cultured with purified interleukin 1, MLR3 surface antigen expression was not observed. Thus MLR3 monoclonal antibody appears to recognize an antigen involved in an early step of T-cell activation related to interleukin 1-dependent functions and on both T lymphocytes and thymocytes.

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Available from: Maria Elisabetta Cosulich
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    • "Our results are in contrast with the initial in vitro data showing that anti-CD3 or PMA-activated human T cells were further induced to proliferate by CD69 targeting, but are in agreement with a posterior observation indicating that Ag-specific T cell proliferation was unaffected in CD69−/− mouse T cells in vivo [27]. Of notice, not all the anti-CD69 MAbs tested in initial works were reported to have this proliferation-enhancing effect on human T cells [43]–[44]. Altogether, more physiological in vitro and in vivo data argue against the initially proposed role for CD69 as a costimulatory molecule. "
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    ABSTRACT: CD69 is rapidly upregulated on T cells upon activation. In this work we show that this is also the case for CD69 expression on dendritic cells (DC). Thus, the expression kinetics of CD69 on both cell types is reminiscent of the one of costimulatory molecules. Using mouse models of transgenic T cells, we aimed at evaluating the effect of monoclonal antibody (MAb)-based targeting and gene deficiency of CD69 expressed by either DC or T cells on the extent of antigen (Ag)-specific T cell priming, which could be the result of a putative role in costimulation as well as on DC maturation and Ag-processing and presentation. CD69 targeting or deficiency of DC did not affect their expression of costimulatory molecules nor their capacity to induce Ag-specific T cell proliferation in in vitro assays. Also, CD69 targeting or deficiency of transgenic T cells did not affect the minimal proliferative dose for different peptide agonists in vitro. In in vivo models of transgenic T cell transfer and local Ag injection, CD69 deficiency of transferred T cells did not affect the extent of the proliferative response in Ag-draining lymph nodes (LN). In agreement with these results, CD69 MAb targeting or gene deficiency of Vaccinia-virus (VACV) infected mice did not affect the endogenous formation of virus-specific CD8(+) T cell populations at the peak of the primary immune response. Altogether our results argue against a possible role in costimulation or an effect on Ag processing and presentation for CD69.
    Full-text · Article · Oct 2012 · PLoS ONE
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    • "The CD69 gene is located within the natural killer (NK) gene complex on mouse chromosome 6 and human chromosome 12 [12,13]. CD69 was initially detected on the surface of activated lymphocytes and is known as a very early activation marker antigen [14-16]. However, CD69 expression is not restricted to these cells, since activated macrophages, neutrophils, and eosinophils can also express CD69 [17-19]. "
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    ABSTRACT: Cluster of differentiation 69 (CD69), an early activation marker antigen on T and B cells, is also expressed on activated macrophages and neutrophils, suggesting that CD69 may play a role in inflammatory diseases. To determine the effect of CD69 deficiency on bleomycin(BLM)-induced lung injury, we evaluated the inflammatory response following intratracheal BLM administration and the subsequent fibrotic changes in wild type (WT) and CD69-deficient (CD69-/-) mice. The mice received a single dose of 3 mg/kg body weight of BLM and were sacrificed at 7 or 14 days post-instillation (dpi). Lung inflammation in the acute phase (7 dpi) was investigated by differential cell counts and cytokine array analyses of bronchoalveolar lavage fluid. In addition, lung fibrotic changes were evaluated at 14 dpi by histopathology and collagen assays. We also used reverse transcription polymerase chain reaction to measure the mRNA expression level of transforming growth factor β1 (TGF-β1) in the lungs of BLM-treated mice. CD69-/- mice exhibited less lung damage than WT mice, as shown by reductions in the following indices: (1) loss of body weight, (2) wet/dry ratio of lung, (3) cytokine levels in BALF, (4) histological evidence of lung injury, (5) lung collagen deposition, and (6) TGF-β1 mRNA expression in the lung. The present study clearly demonstrates that CD69 plays an important role in the progression of lung injury induced by BLM.
    Full-text · Article · Oct 2011 · Respiratory research
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    • "We previously showed that ZPS stimulation upregulates the expression of CD69, an early T-cell activation marker, on CD4 T cells [39]. After TCR stimulation, CD69 is rapidly upregulated by the Ras-MAP kinase signaling pathway [53, 54], suggesting that this pathway may be involved in ZPS-mediated T-cell activation. However, more studies are required to determine if ZPS recognition results in the activation of key proximal TCR signaling molecules, such as Lck, Zap70, Lat, and SLP76 [55]. "
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    ABSTRACT: The detection of pathogen-derived molecules as foreign particles by adaptive immune cells triggers T and B lymphocytes to mount protective cellular and humoral responses, respectively. Recent immunological advances elucidated that proteins and some lipids are the principle biological molecules that induce protective T cell responses during microbial infections. Polysaccharides are important components of microbial pathogens and many vaccines. However, research concerning the activation of the adaptive immune system by polysaccharides gained interest only recently. Traditionally, polysaccharides were considered to be T cell-independent antigens that did not directly activate T cells or induce protective immune responses. Here, we review several recent advances in "carbohydrate immunobiology". A group of bacterial polysaccharides that are known as "zwitterionic polysaccharides (ZPSs)" were recently identified as potent immune modulators. The immunomodulatory effect of ZPSs required antigen processing and presentation by antigen presenting cells, the activation of CD4 T cells and subpopulations of CD8 T cells and the modulation of host cytokine responses. In this review, we also discuss the potential use of these unique immunomodulatory ZPSs in new vaccination strategies against chronic inflammatory conditions, autoimmunity, infectious diseases, allergies and asthmatic conditions.
    Full-text · Article · Dec 2010 · International Journal of Microbiology
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