Inulin-Type ß2-1 Fructans have Some Effect on the Antibody Response to Seasonal Influenza Vaccination in Healthy Middle-Aged Humans.

ß2-1 fructans are prebiotics and, as such, may modulate some aspects of immune function. Improved immune function could enhance the host's ability to respond to infections. There is limited information on the effects of ß2-1 fructans on immune responses in humans. The objective of the study was to determine the effect of a specific combination of long-chain inulin and oligofructose (Orafti(®) Synergy1) on immune function in middle-aged humans, with the primary outcome being response to seasonal influenza vaccination. Healthy middle-aged humans (45-63 years of age) were randomly allocated to consume ß2-1 fructans in the form of Orafti(®) Synergy1 (8 g/day; n = 22) or maltodextrin as control (8 g/day; n = 21) for 8 weeks. After 4 weeks, participants received the 2008/2009 seasonal influenza vaccine. Blood and saliva samples were collected prior to vaccination and 2 and 4 weeks after vaccination. They were used to measure various immune parameters. The primary outcome was the serum concentration of anti-vaccine antibodies. Serum antibody titers against the vaccine and vaccine-specific immunoglobulin concentrations increased post-vaccination. Antibodies to the H3N2-like hemagglutinin type 3, neuraminidase type 2-like strain were higher in the Synergy1 group (P = 0.020 for overall effect of treatment group), as was serum vaccine-specific IgG1 2 weeks post-vaccination (P = 0.028 versus control). There were no other differences between groups in antibody titers or anti-vaccine immunoglobulin concentrations, in blood immune cell phenotypes, or in a range of immune parameters. It is concluded that Orafti(®) Synergy1, a combination of ß2-1 fructans, can enhance some aspects of the immune response in healthy middle-aged adults, but that this is not a global effect.

ß2-1 Fructans have a bifidogenic effect in healthy middle-aged human subjects but do not alter immune responses examined in the absence of an in vivo immune challenge: results from a randomised controlled trial.

ß2-1 fructans are considered to be prebiotics. Current literature indicates that ß2-1 fructans may modulate some aspects of immune function, improve the host's ability to respond to certain intestinal infections, and modify some inflammatory outcomes in human subjects. However, there is a need to find out more about the modulation of immune markers by ß2-1 fructans in humans. Healthy human subjects aged 45-65 years were randomly allocated to ß2-1 fructans (Orafti® Synergy1; 8 g/d; n 22) or the digestible carbohydrate maltodextrin as placebo (n 21) for 4 weeks. Blood, saliva and faecal samples were collected at study entry and after 4 weeks. Immune parameters were measured using the blood and saliva samples and bifidobacteria were measured in the faecal samples. Faecal bifidobacteria numbers increased in the Orafti® Synergy1 group (P < 0·001) and were different at 4 weeks from numbers in the placebo group (P = 0·001). There was no significant effect of Orafti® Synergy1 on any of the immune parameters measured (blood immune cell subsets, total serum Ig, salivary IgA, neutrophil and monocyte phagocytosis of Escherichia coli and respiratory burst in response to E. coli or phorbol ester, natural killer cell activity, T cell activation and proliferation, production of six cytokines by T cells). It is concluded that, compared with maltodextrin, Orafti® Synergy1 has a bifidogenic effect in healthy middle-aged human subjects but does not alter immune responses examined in the absence of an in vivo immune challenge.

ß-Hydroxy-ß-methylbutyrate modifies human peripheral blood mononuclear cell proliferation and cytokine production in vitro.

OBJECTIVE: The main objective was to investigate the potential immunomodulatory effects of ß-hydroxy-ß-methylbutyrate (HMB) in human cells. METHODS: Peripheral blood mononuclear cells were isolated from the blood of eight volunteers and assayed for proliferation, cell cycle progression, surface expression of CD25, intracellular expression of pERK1/2, and cytokine production after in vitro exposure to a range of HMB concentrations (0.1 to 10 mM). RESULTS: Above 1 mM, HMB decreased the extent of proliferation normally observed after stimulation by concanavalin A. The decrease was evident at 10 mM HMB, when the proliferation index was 50% reduced when compared with the absence of HMB. Cell cycle analysis demonstrated an increase in the proportion of cells at the G0-G1 phase at 10 mM HMB. CD25 and pERK1/2 expression were not related to the observed effect on proliferation. HMB affected the concentrations of all five cytokines measured following stimulation. Tumor necrosis factor-α concentration in the culture medium was reduced by ~35% at all HMB concentrations. Th1/Th2 cytokine production was modified toward a Th2 profile when HMB was at 1 or 10 mM. Thus, HMB at 10 mM impairs lymphocyte proliferation and progression through the cell cycle. The lowest concentration used here (0.1 mM) exerted some actions on cytokine production, including decreasing TNF-α production, but not on proliferation and cell cycle progression. CONCLUSION: HMB may be a useful agent to consider for modulation of immune function in specific situations.

Prebiotics, immune function, infection and inflammation: a review of the evidence.

Beta2-1 fructans are carbohydrate molecules with prebiotic properties. Through resistance to digestion in the upper gastrointestinal tract, they reach the colon intact, where they selectively stimulate the growth and/or activity of beneficial members of the gut microbiota. Through this modification of the intestinal microbiota, and by additional mechanisms, beta2-1 fructans may have beneficial effects upon immune function, ability to combat infection, and inflammatory processes and conditions. In this paper, we have collated, summarised and evaluated studies investigating these areas. Twenty-one studies in laboratory animals suggest that some aspects of innate and adaptive immunity of the gut and the systemic immune systems are modified by beta2-1 fructans. In man, two studies in children and nine studies in adults indicate that the adaptive immune system may be modified by beta2-1 fructans. Thirteen studies in animal models of intestinal infections conclude a beneficial effect of beta2-1 fructans. Ten trials involving infants and children have mostly reported benefits on infectious outcomes; in fifteen adult trials, little effect was generally seen, although in specific situations, certain beta2-1 fructans may be beneficial. Ten studies in animal models show benefit of beta2-1 fructans with regard to intestinal inflammation. Human studies report some benefits regarding inflammatory bowel disease (four positive studies) and atopic dermatitis (one positive study), but findings in irritable bowel syndrome are inconsistent. Therefore, overall the results indicate that beta2-1 fructans are able to modulate some aspects of immune function, to improve the host's ability to respond successfully to certain intestinal infections, and to modify some inflammatory conditions.