Differential effect ofBacillus firmus on immune response and enterocyte brush-border enzyme levels in BALB/c and B10.BR mice

Abstract

A nonpathogenic bacterium of external environment possessing remarkable immunomodulatory activity, Bacillus firmus (BF) inactivated with formaldehyde, was given intragastrically to two genetically different mouse strains BALB/c (H-2d) and B10.BR/SnPh (B10.BR, H-2k) reared in conventional (CV) and B10.BR strain also in germ-free (GF) conditions. Repeated intragastric administration of BF (500 micrograms every other day over two weeks, starting at the age of 3 months) significantly enhanced intestinal IgA levels in CV BALB/c mice but did not affect intestinal IgA in CV B10.BR mice. In GF B10.BR mice, IgG levels in sera and intestinal washings increased after BF administration compared to CV B10.BR mice. In CV BALB/c mice, specific activity of enterocyte brush-border enzymes (lactase, gamma-glutamyltransferase, alkaline phosphatase) decreased after BF treatment; sucrase (sucrose alpha-glucosidase) activity was not affected. On the other hand, in B10.BR mice, specific activity of gamma-glutamyltransferase and dipeptidyl peptidase IV were higher after administration of BF in both CV and GF groups relative to untreated controls. The activities of lactase and glucoamylase (glucan 1,4-alpha-glucosidase) were significantly stimulated only in the group of GF B10.BR mice treated with formolized BF. The stimulation of immunoglobulin production after BF treatment was accompanied by changes in the levels of enterocyte brush-border enzymes; this responsiveness to BF treatment was genetically regulated.

The Yakult International Conference, Probiotics & Health 2001, The Three Ages of Man. Was held at The Royal College of Physicians in London on 13-14 September 2001

“…Two age groups of GF mice were associated with B. bifidum CCM 3762 (10 8 CFU/ml) eleven days before the end of the experiment. Specific activities of lactase, sucrase, glucoamylase, alkaline phosphatase (AP), dipeptidyl peptidase IV (DPP IV) and g-glutamyltranspeptidase was determined in isolated jejunal brush-border membranes using substrates -lactose, sucrose, starch, p-nitrophenylphosphate, Gly-L-Pro-4-nitroanilide and 5-L-Glu-(4-nitroanilide), respectively (Kessler et al 1978;Kozakova et al 1998).…”