1. Abstract
The incidence of allergies is increasing in developed countries. Allergies are pro-inflammatory reactions
of the immune system to normally harmless substances, the allergens. Upon recognition of an allergen,
type 2 immune response is activated, which promote IgE-mediated allergies. When the balance
between Th1 and Th2 responses is disturbed allergic reactions may be triggered. In addition, regulatory
T cells (Tregs) producing IL-10 also have the ability to suppress Th2 responses to allergens. Since there
is no cure for food allergies, natural immunomodulators such as edible mushrooms are in the spotlight
because of their medicinal and nutritional properties. Mushroom β-glucans activate Pattern
Recognition Receptors (PRRs) on innate immune cells that subsequently activate the adaptive immune
response. In the present study the immuno-modulating properties of A. bisporus, the white button
mushroom, on the murine immune system were investigated. Specifically, spleen cells previously
stimulated with five A. bisporus varieties, A15, #033, #123, #145 and #188 were re-stimulated with
OVA, anti-CD3 and medium. The secreted levels of cytokines were subsequently measured by ELISA.
Furthermore, the degree of interaction between A. bisporus and BMDC’s and Dectin expressed on 3T3
cells was visualized by flow cytometry. Finally, the secreted level of TNF-α was measured in BMDC’s
stimulated with the same A. bisporus varieties after neutralization with antibodies or inhibiting
compounds binding specific receptors. The results from the bioassays showed that three out of five
varieties were strong immunostimulators. Furthermore, a possible immunomodulating role of A.
bisporus’ protein was indicated. Finally, it was demonstrated that TLR2 played a part in the recognition
of A. bisporus. Although the results obtained were not always conclusive, some insight into the
receptors involved in the recognition of A. bisporus was obtained.