Dataset Information

Effect of Bifidobacterium animalis spp. lactis Bl-04 on Rhinovirus-Induced Colds: A Randomized, Placebo-Controlled, Single-Center, Phase II Trial in Healthy Volunteers.

ABSTRACT:

Background

This study was designed to assess the efficacy of Bifidobacterium animalis ssp. lactis (Bl-04) for prevention of rhinovirus colds and to explore the interactions between the probiotic, the viral infection, the host response and the host microbiome.

Methods

The effect of ingestion of the probiotic Bl-04 was evaluated in a randomized, double-blinded rhinovirus (RV) challenge study. Healthy volunteers recruited from a university community in USA were randomized 1:1 using a computer generated code to ingest either Bl-04 (n=165) or placebo (n=169) for 28 days and were then challenged with RV-A39, and followed for 14 days. All study interactions and sample collection occurred in dedicated clinical research space. The primary analysis was the effect of the probiotic on the incidence of RV-associated illness. (Trial registration: NCT02679807, study complete).

Findings

The first cohort of volunteers was randomized on March 14, 2016 and the last (5^th) cohort was randomized on March 12, 2018. Sixty-three (56%, 95% CI [47%; 66%]) of the 112 subjects in the active group and 60 (50%,95% CI [41%; 59%]) of the 120 subjects in the placebo group had a protocol-defined rhinovirus-associated illness (χ²=0·91, p=0·34). The point estimate of the difference in illness (active-placebo) is 6.3% (95% CI -6.7;19.1). There were no adverse events that were judged as definitely or probably related to the study product.

Interpretation

In this study there was no effect of orally administered Bl-04 on the occurrence of RV-associated illness.

Funding

Danisco Sweeteners Oy (now IFF Health & Biosciences).

SUBMITTER: Turner RB

PROVIDER: S-EPMC8649651 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Backgroundβ-Mannans are abundant and diverse plant structural and storage polysaccharides. Certain human gut microbiota members including health-promoting Bifidobacterium spp. catabolize dietary mannans. Little insight is available on the enzymology of mannan deconstruction in the gut ecological niche. Here, we report the biochemical properties of the first family 5 subfamily 8 glycoside hydrolase (GH5_8) mannanase from the probiotic bacterium Bifidobacterium animalis subsp. lactis Bl-04 (BlMan5_8).ResultsBlMan5_8 possesses a novel low affinity carbohydrate binding module (CBM) specific for soluble mannan and displays the highest catalytic efficiency reported to date for a GH5 mannanase owing to a very high k cat (1828 ± 87 s(-1)) and a low K m (1.58 ± 0.23 g · L(-1)) using locust bean galactomannan as substrate. The novel CBM of BlMan5_8 mediates increased binding to soluble mannan based on affinity electrophoresis. Surface plasmon resonance analysis confirmed the binding of the CBM10 to manno-oligosaccharides, albeit with slightly lower affinity than the catalytic module of the enzyme. This is the first example of a low-affinity mannan-specific CBM, which forms a subfamily of CBM10 together with close homologs present only in mannanases. Members of this new subfamily lack an aromatic residue mediating binding to insoluble cellulose in canonical CBM10 members consistent with the observed low mannan affinity.ConclusionBlMan5_8 is evolved for efficient deconstruction of soluble mannans, which is reflected by an exceptionally low K m and the presence of an atypical low affinity CBM, which increases binding to specifically to soluble mannan while causing minimal decrease in catalytic efficiency as opposed to enzymes with canonical mannan binding modules. These features highlight fine tuning of catalytic and binding properties to support specialization towards a preferred substrate, which is likely to confer an advantage in the adaptation to competitive ecological niches.