PULMONARY BACTERIAL CLEARANCE IN LIPOPOLYSACCHARIDE-INDUCED TOLERANCE VS. SHOCK MURINE MODELS

NAHUEL RODRIGUEZ-RODRIGUES; DAIANA MARTIRE GRECO,; VERÓNICA I. LANDONI; CHIARELLA PAULLA; PABLO SCHIERLOH,; BÁRBARA REARTE; ROBERTO P. MEISS; MARTÍN A. ISTURIZ; FERNÁNDEZ GABRIELA C

Congreso; LIX REUNIÓN CIENTÍFICA ANUAL-LXII REUNIÓN ANUAL; 2014

Repeated inoculation of bacterial lipopolysaccharide (LPS) in mice generates a refractory state, where animals survive lethal doses of LPS and have low amounts of LPS-induced TNF. This state is also associated with defects in antibody responses. Our aim was to compare how the exposure to LPS affects pulmonary bacterial clearance as a measure of innate immune function. For this purpose, we used two models of LPS exposure. In the LPS-tolerance model, tolerance was induced by daily i.v. injections of increasing doses of LPS (5-100 µg/day/mouse) for 7 days. In the LPS-shock model a single high dose of LPS (50 µg/mouse) was administered i.v. Then the animals were challenged intratracheally with intestinal bacteria (5x10 6 CFU) and the number of remaining bacteria in the lung or bronchoalveolar lavage (BAL) was evaluated 4h postinfection on McConkey agar plates. In the LPS-tolerance model the bacterial clearance was higher compared to Control mice (Total CFU. Lung: C= 3.94x106 ±1,02x10 6 , Tol= 1.34x10 6 ±0.90x10 6 . BAL: C= 5.85x105 ±0.57x10 5 , Tol= 6.66x10 4 ±2.22x10 4 , p