The present invention provides a method for reducing an allergic response and treating or preventing an allergic disease, comprising administering a subject in need thereof a therapeutically effective amount of the active ingredient for the treatment or the prevention of allergic diseases, wherein the active ingredient is glyceraldehyde-3-phosphate Dehydrogenase (G3PDH) or the functional variant or fragment thereof. The G3PDH can be isolated from Lactobacillus gasseri PM-A0005 (deposited under Budapest Treaty in the China Center for Type Culture Collection (CCTCC) with Deposit No: M 207039), as well as extract, fraction, and sub-fraction thereof.