IIFP   25103
INSTITUTO DE ESTUDIOS INMUNOLOGICOS Y FISIOPATOLOGICOS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
CHARACTERIZATION OF INNATE IMMUNE RESPONSE IN A MURINE MODEL OF INTRATRACHEAL INFECTION WITH B. abortus 2308.
Autor/es:
FERRERO MC,; FERNANDEZ AG; BONETTO JOSEFINA; FOSSATI CA; COMERCI DJ,; BALDI PC
Lugar:
Mar del Plata
Reunión:
Congreso; LXII Reunión Anual Sociedad Argentina de Inmunología.; 2014
Institución organizadora:
SAI-SAIC
Resumen:
Brucella is a human pathogen that can be acquired by inhalation. We studied the early stages of infection in a murine model of intratracheal inoculation in terms of bacterial dissemination and cytokine/ chemokine response. Balb/c mice were inoculated at 106 or 104 CFU of B. abortus per animal. Lung, liver and spleen homogenates were obtained at 1, 2, 3 and 7 days post infection (pi) and were used for CFU counting and for measuring cytokine and chemokines by ELISA. We found that at 2h pi 77% of the inoculum remains in the lung. During the first 2 days pi, pulmonary bacterial counts in mice receiving the high inoculum dropped from 7.8 to 1.5 (x106) CFU. With the small inoculum, CFU remained constant around 12000 CFU/lung for 4 days pi but increased at day 7 pi. CFU in spleens and livers mimicked the kinetics in lungs, but started at 100 CFU/organ when infected with 106 CFU; and were non-detectable until day 7 pi with the lower inoculum (when they reached 100 CFU/organ). We measured IL-1β, TNF-α, KC, IL-10, IL-12 and MCP-1 in total lung homogenates. We found no significant differences between controls and infected animals when inoculated with 104 CFU at any given time point. When we assessed the high inoculum group the total lung levels of MCP-1 and IL-1β increased significantly only after 3 days pi (p<0.05), while KC and IL-12 increased at 7 days pi (p<0.05). TNF-α levels were lower in infected mice than in controls at days 2 and 3 pi (p<0.01), and IL-10 levels followed the same pattern. In another set of experiments, mice inoculated intratracheally with B. abortus or PBS received E. coli LPS through the same route 1 day later, and lungs were harvested for histopathology 24 h later. A marked decrease in signs of inflammation was noted in lungs of animals from the Brucella/LPS group as compared with the PBS/ LPS group. Our results show that B. abortus infection produces a delayed innate response in the lung and seems to subvert the local inflammatory response to PAMPs.