Modelo biológico para la detección de antígenos alimentarios

Inglés. Biological model for detection of food antigens. Antigenic macromolecules present in food can induce inflammatory allergic reaction in sensitized persons. The aim of the present work is the development of an animal model to detect food antigens based on hypersensitivity reaction after food ingestion. New Zealand rabbits were divided in 5 groups. Group 1 (G1): control. G2: Ovoalbumin (OVA) sensitized. G3: sensitized and orally challenged with OVA. G4: OVA sensitized and phosphate buffer solution challenged (PBS). G5: sensitized and challenged with OVA. Samples from cecum were stained with Alcian Blue pH<1 for mast cells and with silver method for enteroendocrine cells (EEC). Other samples were immunostained with anti CD5 and CD25 monoclonal antibodies. Specific IgE levels were detected by PCA. Histopathology of G5 showed patchy edema, lymphangiectasia and eosinophilic infiltration. Results were expressed as cells per HPF (high power field); Mast cells in G1: 1.33; G2: 12.80 and G5: 10.20. Enteroendocrine cells in surface epithelium: G1: 1.6; G2: 6.0; G5: 4.2 and in deep epithelium: G1: 3.0; G2: 12.0 and G5: 7.3. Lymphocytes CD5+ in G1: 24.21; G2: 22.12 and G5: 23.97 and CD25+ in G1: 12.10; G2: 14.30 and G5: 21.68. Group 3 were similar to G1and G4 to G2. We observed: mast cells increased in number probably due to OVA induced response. EEC showed an increase in sensitized animals because of higher expression of cytoplasmatic granules or differentiation from stem cells. Decrease in EEC number in challenged groups was likely to be based on vesicles release. Total T cells showed no significant differences among groups. CD 25+ cells were higher in sensitized and challenged animals. We concluded that rabbit model of sensitization and oral challenge is valid to study ingested food antigens and potential digestive pathologic reactions.

Español; castellano. Algunos alimentos contienen macromoléculas potencialmente antigénicas capaces de producir reacciones inflamatorias alérgicas en individuos previamente sensibilizados. Nuestro objetivo es desarrollar un modelo animal para detectar antígenos alimentarios en la dieta a partir de la respuesta de hipersensibilidad. Conejos neozelandeses se dividieron en 5 grupos. Grupo 1 (G1): control. G2: sensibilizado con ovoalbúmina (OVA). G3: no sensibilizado y desafiado oralmente con OVA. G4: sensibilizado con OVA y desafiado con buffer fosfato. G5: sensibilizado y desafiado con OVA. Muestras de ciego se colorearon con sales de plata y Alcian Blue (AB) pH <1. Otras se inmunomarcaron con anticuerpos monoclonales anti CD5 y anti CD25. Niveles de IgE específica se detectaron mediante el test de PCA. Histopatológicamente el G5 mostró edema intenso parcheado, linfangiectasias e infiltrado eosinofílico. Se cuantificaron: mastocitos en G1: 1.33 células/ campo; G2: 12.80 y G5: 10.20. Células enteroendócrinas en epitelio superficial: G1: 1.6; G2: 6.0; G5: 4.2 y en epitelio criptal: G1: 3.0; G2: 12.0 y G5: 7.3. Linfocitos CD5+ en G1: 24.21; G2: 22.12 y G5: 23.97 y CD25+ en G1: 12.10; G2: 14.30 y G5: 21.68. El G3 resultó similar al G1 y el G4 al G2. Los mastocitos aumentaron por la inducción de la respuesta inmune por OVA. Las células enteroendócrinas incrementaron en los sensibilizados debido a una mayor expresión de gránulos citoplasmáticos o diferenciación de stem cells y disminuyeron en los desafiados por degranulación citoplasmática. Los linfocitos T totales no mostraron diferencias significativas; pero sí se elevó el número de linfocitos CD25+ en los sensibilizados y desafiados. Concluimos que el conejo sensibilizado y desafiado oralmente, es un modelo válido para estudiar los antígenos presentes en los alimentos y sus reacciones alérgicas digestivas.