The effect of calprotectin on TSLP and IL-25 production from airway epithelial cells

Background

Calprotectin is a heterodimer complex of the S100A8 and S100A9 proteins, and has various functions as an innate mediator at the sites of inflammation.The aim of this study was to elucidate the roles of calprotectin in the eosinophilic chronic rhinosinusitis (ECRS).

Optimizing dendritic cell‐based immunotherapy in multiple myeloma: intranodal injections of idiotype‐pulsed CD40 ligand‐matured vaccines led to induction of type‐1 and cytotoxic T‐cell immune responses in patients

Vaccination with idiotype (Id) protein‐pulsed dendritic cells (DCs) has been explored in multiple myeloma and the results have been disappointing. To improve the efficacy of DC vaccination in myeloma, we investigated the use of Id‐ and keyhole limpet haemocyanin (KLH)‐pulsed, CD40 ligand‐matured DCs administered intranodally. Nine patients with smouldering or stable myeloma without treatment were enrolled and DC vaccines were administered at weekly intervals for a total of four doses. Following vaccination, all patients mounted Id‐specific γ‐interferon T‐cell response. Interleukin‐4 response was elicited in two, and skin delayed‐type hypersensitivity reaction occurred in seven patients. More importantly, Id‐specific cytotoxic T‐cell responses were also detected in five patients. Most if not all patients mounted a positive T‐cell response to KLH following vaccination. At 1‐year follow‐up, six of the nine patients had stable disease, while three patients had slowly progressive disease even during the vaccination period. At 5‐year follow‐up, four of the six patients continued with stable disease. No major side effects were noted. In summary, intranodal administration of Id‐pulsed CD40 ligand‐matured DCs was able to induce Id‐specific T and B‐cell responses in patients. Current efforts are geared towards breaking tumour‐mediated immune suppression and improving clinical efficacy of this immunotherapy.     

T84-intestinal epithelial exosomes bear MHC class II/peptide complexes potentiating antigen presentation by dendritic cells

BACKGROUND & AIMS: Intestinal epithelial cells release antigen-presenting vesicles (exosomes) bearing major histocompatibility complex class II/peptide complexes stimulating specific immune responses in vivo. To characterize further the role of human epithelial exosomes in antigen presentation, their capacity to load antigenic peptides, bind immune target cells, and induce T-cell activation was analyzed in vitro. METHODS: The capacity of exosomes derived from the HLA-DR4-expressing, intestinal epithelial cell line T84 to load the HLA-DR4-specific peptide (3)H-HSA 64-76 and to activate a HLA-DR4-restricted T-cell hybridoma was tested in the presence or absence of human monocyte-derived dendritic cells (DCs). Interaction of fluorescein isothiocyanate-labeled exosomes with T cells and DCs was analyzed by flow cytometry and confocal microscopy. RESULTS: T84-derived exosomes, enriched in CD9, CD81, CD82, and A33 antigen, were capable of binding specifically human serum albumin (HSA) 64-76 peptide on HLA-DR4 molecules and of interacting preferentially with DCs. HSA-loaded exosomes were unable to activate the T-cell hybridoma directly but induced a productive T-cell activation through DCs. When HSA peptide was bound to exosomal HLA-DR4 molecules instead of in a soluble form, the threshold of peptide presentation by DCs was markedly decreased (x10(-3)). CONCLUSIONS: Exosomes released by intestinal epithelial cells bear exogenous peptides complexed to major histocompatibility complex class II molecules and interact preferentially with DCs, strongly potentiating peptide presentation to T cells. Epithelial exosomes constitute a powerful link between luminal antigens and local immune cells by mediating the transfer of tiny amounts of luminal antigenic information and facilitating immune surveillance at mucosal surfaces.