Efecto del virus del síndrome reproductivo y respiratorio porcino (PRRS) en células dendríticas de cerdo derivadas de monocitos / Effect of porcine reproductive and respiratory syndrome (PRRS) virus on porcine monocyte-derived dendritic cells

Dendritic cells (DC) are considered the most important antigen presenting cells of the immune system. Its anatomical location (skin, mucosa and peripheral blood), the expression of receptors to recognize pathogens, the expression of co-stimulatory molecules (CD80/86), the major histocompatibility complex (MHC) class I and II, and the production of cytokines (such as IFN-α, IL-10, IL-12) confers to these cells the characteristic to regulate innate and adaptive immune responses. The objective of this work was to evaluate the effects of the porcine reproductive and respiratory virus (PRRS) in mature DC. DC were generated from blood monocytes using IL-4 and GM-CSF and were stimulated with lipopolysaccharide (LPS) to induce their maturation. The results show that the expression of CD14 and CD172a molecules in infected DC was not affected, while MHC II and CD80/86 expression was diminished. This decrease seems to affect the allogenic proliferation of lymphocytes stimulated with infected DC. On the other hand, the virus increases mRNA expression of IL-10 and TNF-α, and diminishes that for IL-1 β and IL-6. The results obtained could explain, in part, the immunophatology of the disease.

Las células dendríticas (DC) son las presentadoras de antígeno más importantes del sistema inmune. Su localización anatómica (piel, mucosas y sangre periférica), la expresión de receptores para reconocer patógenos, la expresión de moléculas de coestimulación (CD80/86), del complejo principal de histocompatibilidad (MHC) clases I y II, y la producción de citocinas (IFN-α, IL-10, IL-12), les confiere una característica única para regular las respuestas inmune innata y adaptativa. El objetivo de este trabajo fue evaluar el efecto del virus de síndrome reproductivo y respiratorio porcino (PRRS) en DC maduras. Se generaron células dendríticas a partir de monocitos utilizando IL-4 y GM-CSF y se estimularon con lipopolisacárido (LPS) para inducir su maduración. Los resultados muestran que la expresión de las moléculas CD14 y CD172a no se altera en las DC infectadas, mientras que la expresión de MHC II y CD80/86 se ve disminuida. Esta disminución parece afectar la proliferación alogénica de linfocitos estimulados con DC infectadas. Asimismo, el virus aumenta la expresión del ARNm de IL-10 y TNF-α, y disminuye la de IL-1 β e IL-6. Lo anterior explica, en parte, la inmunopatología de la enfermedad.

Impacto de la dieta sobre la inducción de infección con quistes de Giardia lamblia en ratas Sprague-Dawley / Impact of diet on the induction of infection with Giardia lamblia cysts in Sprague-Dawley rats

OBJECTIVE: To assess the effect of malnutrition on the development of giardiasis in Sprague-Dawley rats, using different inoculum sizes of Giardia lamblia cysts. MATERIAL AND METHODS: An experimental study was conducted between 1995 and 1999 at Centro de Investigación, Alimentación y Desarrollo (Center for Research, Food, and Development), in Hermosillo, Sonora, Mexico. The study population consisted of two groups of six to eight experimental units that were fed two different diets and inoculated five different concentrations of Giardia lamblia cysts. Data were collected on excretion of cysts, weight gain, food intake, bowel contents, and macro and microscopic lesions in the intestinal mucosa. Statistical analysis consisted of analysis of variance and residuals. RESULTS: Animals fed with a diet meeting nutritional requirements required an infecting inoculum of 60 cysts, while malnourished rats required only six cysts to develop mucosal lesions. CONCLUSIONS: Weight gain monitored during ten days was not a good indicator of Giardia lamblia infection. Infection depended on cyst inoculum size as well as on the nutritional status of the tested animals.