The major allergen of the Parietaria pollen contains an LPS-binding region with immuno-modulatory activity.

BACKGROUND: The major allergens in Parietaria pollen, Par j 1 and Par j 2, have been identified as lipid transfer proteins. The family of the Par j 1 allergens is composed of two isoforms, which differ by the presence of a 37 amino acid peptide (Par37) exclusive to the Par j 1.0101 isoform. The goal of this study was to elucidate the biological properties of the Par37 peptide. METHODS: In silico analysis, spectrofluorimetric experiments and in vitro cell culture assays were used to identify the biological properties of Par37. In addition, a mouse model of sensitization was used to study the influence of Par37 in the murine immune response. RESULTS: In silico analysis predicted that Par37 displays characteristics of a host defence peptide. Spectrofluorimetric analysis, real-time PCR and ELISA assays demonstrated that Par37 possesses an LPS-binding activity influencing cell signalling in vitro. In RAW264.7 cells, LPS-induced IL-6 and TNF-α transcription and translation were inhibited after preincubation with Par37. Consistent with these data, inhibition of IFN-γ secretion was observed in murine spleen cells and in human PBMC. Finally, mice immunized with the two Par j 1 isoforms differing in the presence or absence of the Par37 peptide showed different immunological behaviours in vivo. CONCLUSIONS: This study demonstrates that the Par j 1.0101 allergen displays LPS-binding activity due to the presence of a 37 amino acid COOH-terminal region and that this region is capable of influencing cytokine and antibody responses in vitro and in vivo.

Alpha-tubulin marker gene of neural territory of sea urchin embryos detected by whole-mount in situ hybridization.

We have used Northern blot and whole-mount in situ hybridizations to analyze the temporal and spatial expression pattern of the Pl alpha 2 alpha-tubulin gene in Paracentrotus lividus sea urchin embryos. The Pl alpha 2 transcript is first detectable at 14 h post-fertilization (blastula stage) and it is only expressed in the oral ectoderm. The amount of transcripts of this gene increases throughout development and accumulates up to the pluteus stage. In this stage the Pl alpha 2 transcript is localized in the neural structures of the embryo. We conclude that the Pl alpha 2 gene is an early neurogenic territory marker. Furthermore we have observed the same localization of the Pl alpha 2 transcript in the Zn(++)- or phenytoin-treated embryos, confirming the animal localization of the Pl alpha 2 transcript and its specific relation to neurogenic territory, whose differentiation starts from few founder cells present at blastula stage.