Probiotic administration reduces lung injuries in a S. pneumoniae infection

RACEDO SILVIA; MEDINA MARCELA; AGÜERO GRACIELA; ALVAREZ SUSANA

Córdoba. Argentina

Congreso; VII Cong. Latinoamericano de Inmunología. ALAI; 2005

Sociedad Latinoamericana de Inmunología

Preventive administration of Lactobacillus casei for 2 days (Lc) reduces lung injuries and improves S.pneumoniae (Spn) clearance.Aim: to study the effect of Lc oral administration on prevention of Spn lung infection analyzing innate and specific immune responses. Mice were fed Lc(109cells/day/mouse),at the end of treatment this group and control mice(C) were intranasally challenged with 106CFU Spn/mouse.Determinations:a)In broncoalveolar fluid (BAL):NBT test for phagocytes activity and pathogen specific IgA(IgAsp) by ELISA;b)In lung homogenate(LH):myeloperoxidase activity(MPO),c)In lung(L) histological slides:IgA+cells by IF,d)In serum(S) and LH:TNF-a and IL-10 by ELISA.Assays were performed before(0d) and after challenge (during 15 days post-infection(dpi)).Lc increased %NBT+cells (0d:C=25.8±0.8 Lc=55.5±1.5 1dpi:C=63,9±1,1 Lc=79,9±1,4) and MPO  at 2dpi(C=7,5±0,5 Lc=12,6±0,6 U/mg protein).IgAsp(mg/l) were higher in Lc group compared with C at 10dpi (C=1,81±0,1 Lc=2,48±0,1).This results correlated with IgA+cells in L(10dpi:Ci=20,3±2,5,Lc2d=46,5±1,5 cells/10fields).Lc induced an earlier increase of L TNF-a at 8 hpi (C=2020±25 Lc=2645±32 pg/ml),showing a lower peak than C at 12 hpi(C=3018±26 Lc=2890±42). In S of Lc TNF-a was lower than C.Previous infection,Lc increased IL-10 in S(C=126±23 Lc=233±26 pg/ml) and L (C=143±23 Lc= 295±41). After infection, IL-10 was higher in L of Lc at 5 dpi (C=280±27 Lc=589±41) and 10dpi(C=351±45 Lc=436±32).IL-10 was increased at 3dpi(C=151±32 Lc=212±25) and 5dpi(C=140±34 Lc=243±27) in S. Lc would induce an activation of distant cells improving innate and specific immune response against pneumococci.This effect was probably exerted by the modulation of cytokine expression