Dietary whole glucan particles do not affect antibody or cell-mediated immune responses to influenza virus vaccination in mice

Influenza virus is a serious health concern. β-glucans derived from plants, bacteria, and fungi have been shown to potentiate immune system responses including those elicited by vaccination. However, in these studies β-glucan was administered as an adjuvant in the vaccine preparation. We hypothesized that addition of a commercially available whole glucan particle supplement to the diet would improve immune response to primary and secondary influenza vaccination in mice. β-glucan was added to pelleted diet and fed to mice at concentrations designed to deliver 0 (control), 1.8 or 90 mg·kg ^-1·day ^-1 to each mouse. Influenza vaccine was given intramuscularly in the left hindlimb and primary and secondary responses were assessed. Supplementation with β-glucan was not effective in boosting immune responses to the vaccine, either in the primary or secondary vaccination experiments. Surprisingly, addition of particulate β-glucan to the vaccine itself also failed to elicit a greater antibody response. These observations suggest that this particular form of β-glucan is ineffective in boosting immune response to intramuscular influenza vaccination. Further study is warranted to determine if the use of different mouse models, different vaccine delivery systems, or β-glucans purified from different strains of bacteria, fungi, or plants could improve outcomes using this or similar protocols.