RESUMEN
Following the 2009 H1N1 influenza pandemic, an increased risk of narcolepsy type 1 was observed. Homology between an H1N1 hemagglutinin and two hypocretin sequences has been reported. T cell reactivity to these peptides was assessed in 81 narcolepsy type 1 patients and 19 HLA-DQ6-matched healthy controls. HLA-DQ6-restricted H1N1 hemagglutinin-specific T cell responses were detected in 28.4% of patients and 15.8% of controls. Despite structural homology between HLA-DQ6-hypocretin and -H1N1 peptide complexes, T cell cross-reactivity was not detected. These results indicate that it is unlikely that cross-reactivity between H1N1 hemagglutinin and hypocretin peptides presented by HLA-DQ6 is involved in the development of narcolepsy.
Asunto(s)
Linfocitos T CD4-Positivos/inmunología , Antígenos HLA-DQ/inmunología , Glicoproteínas Hemaglutininas del Virus de la Influenza/inmunología , Narcolepsia/inmunología , Orexinas/inmunología , Subgrupos de Linfocitos T/inmunología , Adolescente , Adulto , Proteínas del Líquido Cefalorraquídeo/análisis , Niño , Cristalografía por Rayos X , Femenino , Antígenos HLA-DQ/química , Cadenas alfa de HLA-DQ/análisis , Cadenas beta de HLA-DQ/análisis , Glicoproteínas Hemaglutininas del Virus de la Influenza/química , Humanos , Subtipo H1N1 del Virus de la Influenza A , Masculino , Persona de Mediana Edad , Modelos Moleculares , Imitación Molecular , Narcolepsia/etiología , Orexinas/líquido cefalorraquídeo , Orexinas/química , Pandemias , Fragmentos de Péptidos/química , Fragmentos de Péptidos/inmunología , Conformación Proteica , Adulto JovenRESUMEN
BACKGROUND: It is now generally accepted that coeliac disease (CD) is caused by inflammatory T cell responses to gluten peptides bound to HLA-DQ2 or -DQ8 molecules. There is overwhelming evidence that CD patients can mount T cell responses to peptides found in both alpha-gliadin and gamma-gliadin molecules. Assays that would detect the presence or absence of such peptides in food would thus be accurate indicators of safety for consumption by CD patients. AIMS: The development of a sensitive method to detect T cell stimulatory epitopes of alpha-gliadin and gamma-gliadin molecules in food products. METHODS: Monoclonal antibodies (mAb) were raised against peptides encoding the T cell stimulatory epitopes of alpha-gliadin (amino acids (aa) 59-71) and aa gamma-gliadin (aa 142-153 and aa 147-159). These mAb competition assays were developed that quantitatively detect T cell stimulatory epitopes present on both intact proteins and peptides of sizes recognisable by CD4(+) T cells. RESULTS: With the mAb based competition assays, T cell epitopes were detected in pepsin/trypsin digests of wheat proteins and ethanol extracts of various food products, with detection levels lower than those reached with gluten specific T cells. Moreover, the presence of T cell stimulatory epitopes was also detected in preparations of barley, rye, and triticale, other cereals known to be toxic for CD patients. CONCLUSIONS: A new antibody based method has been developed, detecting the presence of T cell stimulatory gluten peptides. This can be used to further ensure the safety of food consumed by CD patients.
Asunto(s)
Epítopos de Linfocito T/análisis , Gliadina/inmunología , Animales , Anticuerpos Monoclonales/inmunología , Unión Competitiva , División Celular/inmunología , Grano Comestible/inmunología , Ensayo de Inmunoadsorción Enzimática/métodos , Epítopos de Linfocito T/inmunología , Alimentos , Análisis de los Alimentos/métodos , Humanos , Activación de Linfocitos , Ratones , Ratones Endogámicos BALB C , Fragmentos de Péptidos/inmunología , Linfocitos T/inmunologíaRESUMEN
Nine patients with leukemic B-lymphoproliferative diseases (B-LPD) were evaluated for development of in vitro recombinant interleukin-2 (rIL-2)-activated killer (LAK) cells. B-cell cultures were established from peripheral blood mononuclear cells (PBMNCs) containing 63% +/- 29% malignant cells. Short-term cultures were tested after 5-day activation with 500 U rIL-2/mL. Long-term cultures were maintained for 4 to 6 weeks by weekly addition of 500 U rIL-2 and autologous irradiated feeder cells. In the first week, the cells decreased considerably in the long-term cultures but thereafter cells proliferated (mainly T cells) on the average 300-fold (range 30- to 1,000-fold). In the short-term cultures, there was a 36% reduction of malignant B cells. In long-term cultures, B cells were reduced from 63% to 8%; three cultures still contained greater than 15% B cells. The CD16-positive cell percentage was comparable in both types of cultures and ranged from 2% to 17%. Effector cells lysing the natural killer (NK)-sensitive cell line K562 could be induced in all patients. Except in patients with chronic lymphocytic leukemia (CLL) and high malignant cell numbers, NK activity was already restored after 5 days. Optimal NK activity was obtained after 1.5 to 2.5 weeks. LAK cells killing NK-resistant lymphoma cell lines showed optimal activity after 2 to 3 weeks of culture. However, LAK cells killing greater than 10% of autologous malignant cells were obtained in only one third of the patients. The discrepancy between strong cytolytic activity against the NK-sensitive (K562) target cells obtained in all patients and the cytotoxic activity against NK-resistant cell lines contrasts with the poor development of LAK cells against autologous tumor cells. This discrepancy does not appear to be explained by soluble inhibitory factors released during the tumor cultures, as allogeneic LAK cells were not inhibited by supernatants from patients' cultures. Further investigations are warranted to reveal cell-mediated inhibition by tumor cells or suppressor cells.