Dietary Supplement Ultimate Immune Enhancer Maitake (grifola frondosa) has been prized in traditional Japanese herbology for hundreds of years. Modern science had identified in Maitake Proteoglucan, Beta-1,3 glucan and Beta-1,6 glucans combined with protein, as an active constituent to support the immune system. Maitake D-fraction is a standardized form of pure and active Proteoglucan, specially developed to be optimal for oral administration.