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Polysaccharides isolated from Açaí fruit induce innate immune responses.

Holderness J, Schepetkin IA, Freedman B, Kirpotina LN, Quinn MT, Hedges JF, Jutila MA - PLoS ONE (2011)

Bottom Line: Similar polyphenol and polysaccharide fractions are found in Acai fruit.Contrary to previous reports, we did not identify agonist activity in the polyphenol fraction; however, the Acai polysaccharide fraction induced robust γδ T cell stimulatory activity in human, mouse, and bovine PBMC cultures.When delivered in vivo, Acai polysaccharide induced myeloid cell recruitment and IL-12 production.

View Article: PubMed Central - PubMed

Affiliation: Department of Immunology and Infectious Diseases, Montana State University, Bozeman, Montana, United States of America.

ABSTRACT
The Açaí (Acai) fruit is a popular nutritional supplement that purportedly enhances immune system function. These anecdotal claims are supported by limited studies describing immune responses to the Acai polyphenol fraction. Previously, we characterized γδ T cell responses to both polyphenol and polysaccharide fractions from several plant-derived nutritional supplements. Similar polyphenol and polysaccharide fractions are found in Acai fruit. Thus, we hypothesized that one or both of these fractions could activate γδ T cells. Contrary to previous reports, we did not identify agonist activity in the polyphenol fraction; however, the Acai polysaccharide fraction induced robust γδ T cell stimulatory activity in human, mouse, and bovine PBMC cultures. To characterize the immune response to Acai polysaccharides, we fractionated the crude polysaccharide preparation and tested these fractions for activity in human PBMC cultures. The largest Acai polysaccharides were the most active in vitro as indicated by activation of myeloid and γδ T cells. When delivered in vivo, Acai polysaccharide induced myeloid cell recruitment and IL-12 production. These results define innate immune responses induced by the polysaccharide component of Acai and have implications for the treatment of asthma and infectious disease.

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Related in: MedlinePlus

Acai fruit does not contain polyphenol-based γδ T cell agonists.A) PVPP-extracted Acai polyphenols were cultured with human PBMCs to detect γδ T cell activation. As a control, APP [1] was used to induce polyphenol-based γδ T cell activation. B) Acai-PS was treated with PVPP to remove polyphenols and the resulting preparation (Acai–PSPR) or untreated Acai-PS was cultured with human PBMCs. γδ T cell activation from the subsequent cultures was measured by FACS as induced CD69 expression. Results are from three individual donors. Error bars represent SD. Experiments were performed independently with respect to donor, experiment date, and Acai-PSPR extraction.
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pone-0017301-g002: Acai fruit does not contain polyphenol-based γδ T cell agonists.A) PVPP-extracted Acai polyphenols were cultured with human PBMCs to detect γδ T cell activation. As a control, APP [1] was used to induce polyphenol-based γδ T cell activation. B) Acai-PS was treated with PVPP to remove polyphenols and the resulting preparation (Acai–PSPR) or untreated Acai-PS was cultured with human PBMCs. γδ T cell activation from the subsequent cultures was measured by FACS as induced CD69 expression. Results are from three individual donors. Error bars represent SD. Experiments were performed independently with respect to donor, experiment date, and Acai-PSPR extraction.

Mentions: Since earlier reports demonstrated immunomodulatory activity of Acai polyphenols [34]–[36] and we have found that some polyphenols are potent γδ T cell agonists [1], [3], we purified polyphenols from Acai and tested them for activity. As shown in Figure 2A, purified Acai polyphenols did not increase CD69 expression on γδ T cells at dosages nearly ten times higher than the polyphenol agonist, Apple Polyphenol (APP) [1]. Also, there was no shift in the dose response curve of Acai-PS in which polyphenols were removed (Acai-PSPR) by PVPP pre-treatment (Figure 2B). These results indicate that the previous reports describing polyphenol-induced immune responses were not a result of activated γδ T cells.


Polysaccharides isolated from Açaí fruit induce innate immune responses.

Holderness J, Schepetkin IA, Freedman B, Kirpotina LN, Quinn MT, Hedges JF, Jutila MA - PLoS ONE (2011)

Acai fruit does not contain polyphenol-based γδ T cell agonists.A) PVPP-extracted Acai polyphenols were cultured with human PBMCs to detect γδ T cell activation. As a control, APP [1] was used to induce polyphenol-based γδ T cell activation. B) Acai-PS was treated with PVPP to remove polyphenols and the resulting preparation (Acai–PSPR) or untreated Acai-PS was cultured with human PBMCs. γδ T cell activation from the subsequent cultures was measured by FACS as induced CD69 expression. Results are from three individual donors. Error bars represent SD. Experiments were performed independently with respect to donor, experiment date, and Acai-PSPR extraction.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3046208&req=5

pone-0017301-g002: Acai fruit does not contain polyphenol-based γδ T cell agonists.A) PVPP-extracted Acai polyphenols were cultured with human PBMCs to detect γδ T cell activation. As a control, APP [1] was used to induce polyphenol-based γδ T cell activation. B) Acai-PS was treated with PVPP to remove polyphenols and the resulting preparation (Acai–PSPR) or untreated Acai-PS was cultured with human PBMCs. γδ T cell activation from the subsequent cultures was measured by FACS as induced CD69 expression. Results are from three individual donors. Error bars represent SD. Experiments were performed independently with respect to donor, experiment date, and Acai-PSPR extraction.
Mentions: Since earlier reports demonstrated immunomodulatory activity of Acai polyphenols [34]–[36] and we have found that some polyphenols are potent γδ T cell agonists [1], [3], we purified polyphenols from Acai and tested them for activity. As shown in Figure 2A, purified Acai polyphenols did not increase CD69 expression on γδ T cells at dosages nearly ten times higher than the polyphenol agonist, Apple Polyphenol (APP) [1]. Also, there was no shift in the dose response curve of Acai-PS in which polyphenols were removed (Acai-PSPR) by PVPP pre-treatment (Figure 2B). These results indicate that the previous reports describing polyphenol-induced immune responses were not a result of activated γδ T cells.

Bottom Line: Similar polyphenol and polysaccharide fractions are found in Acai fruit.Contrary to previous reports, we did not identify agonist activity in the polyphenol fraction; however, the Acai polysaccharide fraction induced robust γδ T cell stimulatory activity in human, mouse, and bovine PBMC cultures.When delivered in vivo, Acai polysaccharide induced myeloid cell recruitment and IL-12 production.

View Article: PubMed Central - PubMed

Affiliation: Department of Immunology and Infectious Diseases, Montana State University, Bozeman, Montana, United States of America.

ABSTRACT
The Açaí (Acai) fruit is a popular nutritional supplement that purportedly enhances immune system function. These anecdotal claims are supported by limited studies describing immune responses to the Acai polyphenol fraction. Previously, we characterized γδ T cell responses to both polyphenol and polysaccharide fractions from several plant-derived nutritional supplements. Similar polyphenol and polysaccharide fractions are found in Acai fruit. Thus, we hypothesized that one or both of these fractions could activate γδ T cells. Contrary to previous reports, we did not identify agonist activity in the polyphenol fraction; however, the Acai polysaccharide fraction induced robust γδ T cell stimulatory activity in human, mouse, and bovine PBMC cultures. To characterize the immune response to Acai polysaccharides, we fractionated the crude polysaccharide preparation and tested these fractions for activity in human PBMC cultures. The largest Acai polysaccharides were the most active in vitro as indicated by activation of myeloid and γδ T cells. When delivered in vivo, Acai polysaccharide induced myeloid cell recruitment and IL-12 production. These results define innate immune responses induced by the polysaccharide component of Acai and have implications for the treatment of asthma and infectious disease.

Show MeSH
Related in: MedlinePlus