RESUMO
Peanut and buckwheat induce a severe allergic reaction, anaphylaxis, which is considered to be mediated by immunoglobulin E (IgE). We identified in this study a new IgE-binding epitope of the peanut allergen that cross-reacted with buckwheat. The phosphate-buffered saline-soluble fraction of buckwheat inhibited the binding between IgE and the peanut allergen. A cross-reactive peptide was isolated from the α-chymotrypsin hydrolysate of peanut. Based on the amino acid sequence and mass spectrometric analysis data, the peptide was identified as Ser-Asp-Gln-Thr-Arg-Thr-Gly-Tyr (SDQTRTGY); this sequence is identical to amino acids 2-9 in the N-terminal hydrophilic domain of oleosin 3 which is located on the surface of the lipid storage body. Synthetic SDQTRTGY was found to bind with IgE in the sera of all eight peanut-allergic patients tested. Since many foods of plant origin contain oleosin, the possibility of an anaphylactic cross-reaction in allergic patients should always be considered.
Assuntos
Alérgenos/química , Antígenos de Plantas/química , Arachis/química , Fagopyrum/química , Imunoglobulina E/química , Hipersensibilidade a Amendoim/imunologia , Proteínas de Plantas/química , Alérgenos/imunologia , Sequência de Aminoácidos , Antígenos de Plantas/imunologia , Arachis/imunologia , Ligação Competitiva , Soluções Tampão , Quimotripsina/química , Reações Cruzadas , Fagopyrum/imunologia , Humanos , Imunoglobulina E/imunologia , Dados de Sequência Molecular , Proteínas de Plantas/imunologia , Estrutura Terciária de Proteína , Proteólise , Homologia de Sequência de AminoácidosRESUMO
Oseltamivir, an ester-type prodrug of the neuraminidase inhibitor [3R,4R,5S]-4-acetamido-5-amino-3-(1-ethylpropoxy)-1-cyclohexene-1-carboxylate phosphate (Ro 64-0802), has been developed for the treatment of A and B strains of the influenza virus but has neuropsychiatric and other side effects. In this study, we characterized the transport across intestinal epithelial cells and the absorption of oseltamivir in rats. Uptake by Caco-2 cells (human carcinoma cell line) and HeLa cells transfected with peptide transporter 1 (HeLa/PEPT1) was time- and temperature-dependent and was inhibited by typical PEPT1 inhibitors such as glycyl-sarcosine (Gly-Sar). The uptake by Caco-2 cells and HeLa/PEPT1 was saturable, with similar K(m) values. Oseltamivir absorption in adult rats was greatly reduced by simultaneous administration of milk, casein, or Gly-Sar. Furthermore, the plasma and brain concentrations of oseltamivir were higher in fasting than in nonfasting rats after oral administration. These results suggest that oseltamivir is a substrate of PEPT1 and that PEPT1 is involved in its intestinal absorption.