RESUMO
Controlled infection with intestinal nematodes has therapeutic potential for preventing the symptoms of allergic and autoimmune diseases. Here, we engineered larvae of the filarial nematode Litomosoides sigmodontis as a vaccine strategy to induce adaptive immunity against a foreign, crosslinked protein, chicken egg ovalbumin (OVA), in the absence of an external adjuvant. The acylation of filarial proteins with fluorescent probes or biotin was not immediately detrimental to larval movement and survival, which died 3 to 5 days later. At least some of the labeled and skin-inoculated filariae migrated through lymphatic vessels to draining lymph nodes. The immunization potential of OVA-biotin-filariae was compared to that of an OVA-bound nanoparticulate carrier co-delivered with a CpG adjuvant in a typical vaccination scheme. Production of IFNγ and TNFα by restimulated CD4+ cells but not CD8+ confirmed the specific ability of filariae to stimulate CD4+ T cells. This alternative method of immunization exploits the intrinsic adjuvancy of the attenuated nematode carrier and has the potential to shift the vaccination immune response towards cellular immunity.
Assuntos
Adjuvantes Imunológicos/administração & dosagem , Hipersensibilidade a Ovo/imunologia , Filarioidea/imunologia , Larva/imunologia , Ovalbumina/imunologia , Imunidade Adaptativa , Animais , Linfócitos T CD4-Positivos/imunologia , Galinhas , Hipersensibilidade a Ovo/etiologia , Filarioidea/genética , Proteínas de Helminto/administração & dosagem , Proteínas de Helminto/genética , Proteínas de Helminto/imunologia , Humanos , Imunização , Larva/genética , Camundongos , Camundongos Endogâmicos C57BL , Ovalbumina/administração & dosagem , Ovalbumina/efeitos adversos , Ovalbumina/químicaRESUMO
We have identified colorectal distension (CRD)-responsive neurons in the anterior cingulate cortex (ACC) and demonstrated that persistence of a heightened visceral afferent nociceptive input to the ACC induces ACC sensitization. In the present study, we confirmed that rostral ACC neurons of sensitized rats [induced by chicken egg albumin (EA)] exhibit enhanced spike responses to CRD. Simultaneous in vivo recording and reverse microdialysis of single ACC neurons showed that a low dose of glutamate (50 microM) did not change basal ACC neuronal firing in normal rats but increased ACC neuronal firing in EA rats from 18 +/- 2 to 32 +/- 3.8 impulses/10 s. A high dose of glutamate (500 microM) produced 1.95-fold and a 4.27-fold increases of ACC neuronal firing in sham-treated rats and in EA rats, respectively, suggesting enhanced glutamatergic transmission in the ACC neurons of EA rats. Reverse microdialysis of the 3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA)/kainite receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX; 10 microM) reduced basal and abolished CRD-induced ACC neuronal firing in normal rats. In contrast, microdialysis of N-methyl-d-aspartate (NMDA) receptor antagonist AP5 had no effect on ACC neuronal firing in normal rats. However, AP5 produced 86% inhibition of ACC neuronal firing evoked by 50 mmHg CRD in the EA rats. In conclusion, ACC nociceptive transmissions are mediated by glutamate AMPA receptors in the control rats. ACC responses to CRD are enhanced in viscerally hypersensitive rats. The enhancement of excitatory glutamatergic transmission in the ACC appears to mediate this response. Furthermore, NMDA receptors mediate ACC synaptic responses after the induction of visceral hypersensitivity.
Assuntos
Anafilaxia/metabolismo , Córtex Cerebral/metabolismo , Doenças do Colo/metabolismo , Hipersensibilidade a Ovo/complicações , Hiperalgesia/metabolismo , Receptores de AMPA/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Transmissão Sináptica , 2-Amino-5-fosfonovalerato/farmacologia , 6-Ciano-7-nitroquinoxalina-2,3-diona/farmacologia , Anafilaxia/etiologia , Anafilaxia/fisiopatologia , Animais , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/fisiopatologia , Doenças do Colo/etiologia , Doenças do Colo/fisiopatologia , Modelos Animais de Doenças , Hipersensibilidade a Ovo/etiologia , Hipersensibilidade a Ovo/metabolismo , Hipersensibilidade a Ovo/fisiopatologia , Proteínas do Ovo/toxicidade , Antagonistas de Aminoácidos Excitatórios/farmacologia , Potenciais Pós-Sinápticos Excitadores , Ácido Glutâmico/metabolismo , Hiperalgesia/etiologia , Hiperalgesia/fisiopatologia , Masculino , Microdiálise , Plasticidade Neuronal , Medição da Dor , Limiar da Dor , Pressão , Ratos , Ratos Sprague-Dawley , Receptores de AMPA/antagonistas & inibidores , Receptores de N-Metil-D-Aspartato/antagonistas & inibidores , Transmissão Sináptica/efeitos dos fármacosRESUMO
BACKGROUND: The prevalence of food anaphylaxis due to masked allergens has increased within the last 10 years. Contamination of manufactured products by food allergens is a key concern for food industries. OBJECTIVE: To determine quantities eliciting reactions in patients who have an IgE-dependent food allergy, thanks to standardized oral provocation tests. To evaluate the subsequent levels of sensitivity required for the detection tests of allergens for egg, peanut, milk and sesame. METHODS: Prick-in-prick tests, Cap system RAST, and single or double-blind placebo-controlled food challenges (SBPCFC or DBPCFC) were performed. The doses of natural food were gradually increased from 5 to 5000 mg for solid food and from 1 to 30 mL for peanut oil, sunflower oil, soy oil and sesame oil. RESULTS: Data from 125 positive oral challenges to egg, 103 to peanut, 59 to milk and 12 to sesame seeds were analysed. Haemodynamic modifications were observed in 2%, 3%, 1.7%, and 8% of the oral challenges (OCs) to egg, peanut, milk and sesame, respectively. Respiratory symptoms were observed in 12%, 20%, 10% and 42% of egg, peanut milk and sesame allergies, respectively. A cumulative reactive dose inferior or equal to 65 mg of solid food or 0.8 mL of milk characterized 16%, 18%, 5% and 8% of egg, peanut, milk and sesame allergies, respectively. 0.8% of egg allergies, 3.9% of peanut allergies, and 1.7% of milk allergies reacted to 10 mg or less of solid food or to 0.1 mL for milk. The lowest reactive threshold has been observed at less than 2 mg of egg; 5 mg of peanut, 0.1 mL of milk and 30 mg of sesame seed. Ten out of 29 OC with peanut oil, two out of two OC with soy oil and three out of six OC with sunflower oil were positive. Five out six OC with sesame oil were positive: 1 and 5 mL induced an anaphylactic shock. CONCLUSION: The risk of asthma and anaphylactic shock to sesame and peanut is confirmed. Minimal reactive quantities show that, in order to guarantee a 95% safety for patients who are allergic to egg, peanut and milk, and on the basis of consumption of 100 g of food, the detection tests should ensure a sensitivity of 10 p.p.m. for egg, 24 p.p.m. for peanut and 30 p.p.m. for milk proteins. Oil allergies being considered, the limit of sensitivity should fall to 5 p.p.m.