Binding of DC-HIL to Dermatophytic Fungi Induces Tyrosine Phosphorylation and Potentiates Antigen Presenting Cell Function

Department of Dermatology, The University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.
The Journal of Immunology (Impact Factor: 4.92). 10/2009; 183(8):5190-8. DOI: 10.4049/jimmunol.0901319
Source: PubMed


APCs express receptors recognizing microbes and regulating immune responses by binding to corresponding ligands on immune cells. Having discovered a novel inhibitory pathway triggered by ligation of DC-HIL on APC to a heparin/heparan sulfate-like saccharide of syndecan-4 on activated T cells, we posited DC-HIL can recognize microbial pathogens in a similar manner. We showed soluble recombinant DC-HIL to bind the dermatophytes Trichophyton rubrum and Microsporum audouinii, but not several bacteria nor Candida albicans. Dermatophyte binding was inhibited completely by the addition of heparin. Because DC-HIL contains an ITAM-like intracellular sequence, we questioned whether its binding to dermatophytes can induce tyrosine phosphorylation in dendritic cells (DC). Culturing DC with T. rubrum (but not with C. albicans pseudohyphae) induced phosphorylation of DC-HIL, but not when the tyrosine residue of the ITAM-like sequence was mutated to phenylalanine. To examine the functional significance of such signaling on DC, we cross-linked DC-HIL with mAb (surrogate ligand), which not only induced tyrosine phosphorylation but also up-regulated expression of 23 genes among 662 genes analyzed by gene-array, including genes for profilin-1, myristoylated alanine rich protein kinase C substrate like-1, C/EBP, LOX-1, IL-1beta, and TNF-alpha. This cross-linking also up-regulated expression of the activation markers CD80/CD86 and heightened APC capacity of DC to activate syngeneic T cells. Our findings support a dual role for DC-HIL: inhibition of adaptive immunity following ligation of syndecan-4 on activated T cells and induction of innate immunity against dermatophytic fungi.

Download full-text


Available from: Jin-Sung Chung
  • Source
    • "Under these conditions, the hemITAM tyrosine residue of GPNMB became phosphorylated, which induced widespread changes in gene and protein expression, including increased cytokine secretion (TNFα, IL-1β).60 This activation of GPNMB stimulated dendritic cell maturation and augmented their ability to potentiate the activation of naive T-cells.60 While these findings are strongly suggestive of functional hemITAM-based signaling in GPNMB, more research is needed to definitively characterize the role of this motif when GPNMB is expressed in immune or non-immune cells. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Molecularly targeted therapies are rapidly growing with respect to their clinical development and impact on cancer treatment due to their highly selective anti-tumor action. However, many aggressive cancers such as triple-negative breast cancer (TNBC) currently lack well-defined therapeutic targets against which such agents can be developed. The identification of tumor-associated antigens and the generation of antibody drug-conjugates represent an emerging area of intense interest and growth in the field of cancer therapeutics. Glycoprotein non-metastatic b (GPNMB) has recently been identified as a gene that is over-expressed in numerous cancers, including TNBC, and often correlates with the metastatic phenotype. In breast cancer, GPNMB expression in the tumor epithelium is associated with a reduction in disease-free and overall survival. Based on these findings, glembatumumab vedotin (CDX-011), an antibody-drug conjugate that selectively targets GPNMB, is currently being investigated in clinical trials for patients with metastatic breast cancer and unresectable melanoma. This review discusses the physiological and potential pathological roles of GPNMB in normal and cancer tissues, respectively, and details the clinical advances and challenges in targeting GPNMB-expressing malignancies.
    Full-text · Article · Jul 2013 · OncoTargets and Therapy
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Dermatophytes are hyphomycetes that can degrade keratin. This puts them in a position to cause infections of the keratin-containing superficial skin. The resulting clinical picture is called tinea. The pathogenesis and course of tinea is decisively determined by pathogen-related factors and by the defense mechanisms of the host. An infection starts with an adherence of fungal propagules, followed by the formation of hyphae that can spread within the tissue. This process is accompanied by a release of fungal enzymes and other pathogenic factors. Next keratinocytes are activated, the epidermal barrier is destroyed, epidermal proliferation is enhanced and defensins are expressed within the epidermis. In addition, innate and specific immune responses are initiated, involving neutrophilic granulocytes, macrophages, antibodies and T cells. The cellular mechanisms are thought to be crucial for healing. Special conditions apply to nail infections, because within nail plates the fungi are not accessible to effective defense mechanisms, as well as to infections of hair follicles that contain specific concentrations of steroid hormones. Dermatophytes that penetrate into the dermis can cause granulomatous inflammatory reactions and systemic immune reactions are supposed to be a trigger of so-called id reactions.
    Preview · Article · Oct 2010 · Journal der Deutschen Dermatologischen Gesellschaft
  • [Show abstract] [Hide abstract]
    ABSTRACT: Cancer is a complex disease with interactions between normal and neoplastic cells. Since current therapies for cancer largely rely on drugs or radiation that kill dividing cells or block cell division, these treatments may have severe side effects on normal proliferating cells in patients with cancer. Recently, immunotherapeutic approaches for cancer therapy, by which monoclonal antibodies (Mabs) target tumor specific antigens, have shown great potential. Glycoprotein non-metastatic melanoma protein B(Gpnmb)/Osteoactivin (OA) is a transmembrane glycoprotein highly expressed in various types of cancer. Gpnmb/OA promotes the migration, invasion and metastasis of tumor cells. CR 011-vcMMAE is a Mab-drug conjugate being developed for the treatment of Gpnmb/OA-expressing cancers. Gpnmb/OA represents an attractive target in cancer immunotherapy and CR011-vcMMAE holds promise as a reagent in targeted therapy for Gpnmb/OA-expressing malignancies.
    No preview · Article · Jan 2012 · Neoplasma
Show more