The nasal mucosal late allergic reaction to grass pollen involves type 2 inflammation (IL-5 and IL-13), the inflammasome (IL-1β), and complement

Non-invasive mucosal sampling (nasosorption and nasal curettage) was used following nasal allergen challenge with grass pollen in subjects with allergic rhinitis, in order to define the molecular basis of the late allergic reaction (LAR). It was found that the nasal LAR to grass pollen involves parallel changes in pathways of type 2 inflammation (IL-4, IL-5 and IL-13), inflammasome-related (IL-1β), and complement and circadian-associated genes. A grass pollen nasal spray was given to subjects with hay fever followed by serial sampling, in which cytokines and chemokines were measured in absorbed nasal mucosal lining fluid, and global gene expression (transcriptomics) assessed in nasal mucosal curettage samples. Twelve of 19 subjects responded with elevations in interleukin (IL)-5, IL-13, IL-1β and MIP-1β/CCL4 protein levels in the late phase. In addition, in these individuals whole-genome expression profiling showed upregulation of type 2 inflammation involving eosinophils and IL-4, IL-5 and IL-13; neutrophil recruitment with IL-1α and IL-1β; the alternative pathway of complement (factor P and C5aR); and prominent effects on circadian-associated transcription regulators. Baseline IL-33 mRNA strongly correlated with these late-phase responses, whereas a single oral dose of prednisone dose-dependently reversed most nasal allergen challenge-induced cytokine and transcript responses. This study shows that the LAR to grass pollen involves a range of inflammatory pathways and suggests potential new biomarkers and therapeutic targets. Furthermore, the marked variation in mucosal inflammatory events between different patients suggests that in the future precision mucosal sampling may enable rational specific therapy.

Characterization of a new member of the TNF family expressed on antigen presenting cells

The TNF family is involved in the regulation of the immune system, and its members have been implicated in a variety of biological events such as apoptosis, cell proliferation, differentiation and survival. Here we present a new member of the TNF family, tumor necrosis factor superfamily member 20 (TNFSF20) that we have identified from the expressed sequence tag (EST) database and characterized. The human protein is a 285 amino acid long type II transmembrane protein and is 19% homologous to TNF in its extra-cellular domain. TNFSF20 is expressed at the surface of antigen presenting cells such as cells of the macrophagemonocyte lineage and dendritic cells. After treatment with bacterial lipopolysaccharide (LPS), TNFSF20 expression is downregulated at the surface of the expresssing cells, suggesting that the membrane-bound protein gets cleaved, and that a soluble factor is released in the extra-cellular compartment. The soluble form of the recombinant TNFSF20 induces proliferation of resting peripheral blood monocytes (PBMC) and cell death of activated lymphocytes. TNFSF20 might therefore play a critical role in the regulation of cell-mediated immune responses.

The product of the adenovirus intermediate gene IVa2 is a transcriptional activator of the major late promoter

During the course of lytic infection, the adenovirus major late promoter (MLP) is induced to high levels after replication of viral DNA has started. We had previously shown that sequence elements located downstream of the MLP start site were implicated in this late-specific transcriptional activation (DE1, between +85 and +98; DE2, between +100 and +120). Two positive transcription factors involved in this activation have been detected. DEF-A, which specifically binds to DE1 and also to the 3' portion of DE2 (DE2a), and DEF-B, which interacts with the 5' part of DE2 (DE2b). When present together, these two proteins cooperatively assemble onto the DE2 element. We now report the purification of DEF-B and show that it is identical to the product of the adenovirus IVa2 gene product. This conclusion is based on microsequence analysis of DEF-B as well as on the inhibitory effect of antibodies against IVa2 on the DNA-binding activity of DEF-B and also on DE-dependent in vitro transcription. In addition, we show that bacterially synthesized IVa2 protein binds to the DE sequences with the same specificity as DEF-B. Finally, in transfected cells, a recombinant IVa2 protein stimulates MLP activity in a DE-dependent fashion. The physiological implications of these findings are discussed.

Identification of a novel downstream binding protein implicated in late-phase-specific activation of the adenovirus major late promotor

The adenovirus major late promotor (MLP) is induced to very high levels after the onset of the viral DNA replication. Previous studies have identified sequence elements located downstream of the MLP startsite (DE1, between +85 and +98; DE2, between +100 and +120) implicated, together with the upstream promoter element, in this late-phase-specific transcriptional activation. One protein (DEF, now renamed DEF-A), induced during the late phase of viral infection, has been identified and shown to bind to the DE1 element (Jansen-Durr et al., 1989, J. Virol. 63, 5124-5132). Here we report about a distinct late-phase-specific protein (DEF-B) and its interactions with DEF-A. DNA-binding studies reveal that DEF-B interacts with the 5' part of DE2 (DE2b), whereas DEF-A, besides its interaction with DE1, also binds to the 3' portion of DE2 (DE2a), but with a lower affinity than for DE1. Furthermore, when added together, DEF-A and DEF-B cooperatively assemble onto the DE2 element as a heteromeric complex which is substantially more stable than the complexes formed by each protein alone. Using an in vivo transcriptional assay of the MLP, we show that DEF-A and DEF-B both have intrinsic transactivating properties.