Study of the effect of Enterococcus faecalis MR99 on innate immune system in BALB/c mice

CASTRO MS; ANDINO PJ; CECI MA; SPARO MD; MANGHI MA

Córdoba, Argentina

Congreso; VII Congreso Latinoamericano de Inmunología; 2005

Asociación Latinoamericana de Inmunología

Enterococcus faecalis MR99 (Ef) is an environmental strain that produces a wide spectrum bacteriocin. Previously, we demonstrated that Ef adheres, implants and persists in the gut of BALB/c mice which were orally pretreated with this bacterium. In this work, we studied the effect of Ef on innate immune system in naive and Ef orally pretreated BALB/c mice. Spleen cell proliferation (3H thymidine uptake) and the cytokine profile (ELISA) were evaluated after ConA and ConA + Ef stimuli. Beside, TNFa, IL-6, IL-12p40 and IL-10 production was studied in peritoneal macrophages culture stimulated with different concentrations of Ef (105-107 cel/ml). Spleen cells of mice Con A (cpm ± SD) Con A + Ef (cpm ± SD) Naive 28.150 ± 8.415 16.880 ± 63.26 Ef pretreated 15.990 ± 4.830 - The T cell proliferation was inhibited by Ef action but INFg and IL-5 levels were similar in both groups of animals (Th1/Th2 response). All Ef stimuli induced peritoneal macrophage to produce IL-6, IL-12 and TNFa (704.0 ± 143.1, 104.6 ± 3.2 and 308.0 ± 15.0 pg/ml, respectively). Only 107 cel/ml Ef stimulus induced the IL-10 production (448.6 ± 44.3 pg/ml). Our results suggest that Ef is an excellent candidate to be used as immune response modulator since it would be able to suppress or intensify inflammatory responses.