Modulation effect of Lactobacillus acidophilus KLDS 1.0738 on gut microbiota and TLR4 expression in β-lactoglobulin-induced allergic mice model

OBJECTIVES

β-lactoglobulin (β-Lg)-sensitized mice model was employed to investigate the correlation between Lactobacillus acidophilus KLDS 1.0738 (Lap KLDS 1.0738) modulating gut microbiota and inducting Toll-like receptors (TLRs) expression.

METHODS

The alterations of mice fecal microbiota were analyzed by 16S rRNA gene sequencing. The serum cytokines production and TLR4/NF-κB mRNA expression in the colon tissues were measured by ELISA kit and quantitative RT-PCR, respectively.

RESULTS

The results showed that Lap KLDS 1.0738 pretreatment attenuated β-Lg-induced hypersensitivity, accompanied with a diminished expression of TLR4/NF-κB signaling. Moreover, oral administration of Lap KLDS 1.0738 improved the richness and diversity of fecal microbiota, which was characterized by fewer Proteobacteria phylum and Helicobacteraceae family, and higher Firmicutes phylum and Lachnospiraceae family than allergic group. Notably, TLR4/NF-κB expression was positively correlated with the family of Helicobacteraceae in allergic group, but negatively correlated with the family of Lachnospiraceae, Ruminococcaceae and anti-inflammatory cytokines level. A significant positive correlation was observed between TLR4/NF-κB expression and the production of histamine, total IgE and pro-inflammatory cytokines.

CONCLUSIONS

Intake of Lap KLDS 1.0738 can influence the gut bacterial composition, which might result in recognizing TLRs signaling so as to inhibit allergic response.

[An experimental study of a lactoglobulin preparation against opportunistic bacteria and salmonellae]

A preclinical study of seven batches of lactoglobulin, a new biological preparation against opportunistic bacteria and salmonellae, has been carried out. High antibacterial activity of the preparation with respect to the virulent forms of Salmonella typhimurium, Salmonella enteritidis, Pseudomonas aeruginosa, Klebsiella pneumoniae, Proteus vulgaris, Proteus mirabilis has been established. The preparation has been shown to be safe and nontoxic. The 4-year term of its storage at a temperature of 6 degrees +/- 4 degrees C has been substantiated.

Killing of Actinobacillus actinomycetemcomitans by human lactoferrin

Actinobacillus actinomycetemcomitans is a fastidious, facultative gram-negative rod associated with endocarditis, certain forms of periodontal disease, and other focal infections. Human neutrophils have demonstrated bactericidal activity against A. actinomycetemcomitans, and much of the oxygen-dependent killing has been attributed to the myeloperoxidase-H2O2-halide system. However, the contribution of other neutrophil components to killing activity is obscure. Lactoferrin, an iron-binding glycoprotein, is a major constituent of neutrophil-specific granules and is also found in mucosal secretions. In this report, we show that human lactoferrin is bactericidal for A. actinomycetemcomitans. Killing activity required an unsaturated (iron- and anion-free) molecule that produced a 2-log decrease in viability within 120 min at 37 degrees C at a concentration of 1.9 microM. Besides exhibiting concentration dependence, killing kinetics were affected by minor variations in temperature and pH. Magnesium, a divalent cation thought to stabilize lipopolysaccharide interactions on the surface of gram-negative organisms, enhanced lactoferrin killing of A. actinomycetemcomitans, while other cations, such as potassium and calcium, had no effect. Our data suggest that lactoferrin contributes to killing of A. actinomycetemcomitans by human neutrophils and that it may also play a significant role in innate secretory defense against this potential periodontopathogen.

[Antibrucellosis lactoglobulin and a study of its therapeutic action under experimental conditions]

Antibrucellosis lactoglobulin obtained by the author had higher specific antibody titres (1 : 81920) than the gamma-globulin batches prepared earlier from the bovine blood serum (1 : 3200). The suggested antibrucellosis lactoglobulin was harmless, of low reactogenicity and produced a definite therapeutic action when administrated to the infected animals. Since lactoglobulin is less expensive than gamma-globulin further work on the improvement of technology of obtaining the former and on the elaboration of the most effective schemes of its use are of expedience.