Together with chitin, the β-glucans are components of mycetes' cell walls. A high level of biological efficiency has been found in β-glucans, especially β-1,3-D-glucans and β-1,6-D-glucans isolated from some basidiomycetes. (Biological efficiency refers to the relative ability of β-glucans to promote a desired response, for example to induce leukocyte activation and to produce inflammatory mediators.) These polysaccharides increase the number of Th1 lymphocytes, which help protect organisms against allergic reactions. A number of β-glucans, for example pleuran from Oyster (Pleurotus spp.) mushrooms or lentinan from Shiitake (Lentinus edodes) mushrooms, have shown marked anticarcinogenic activity. In addition to having an immunity-stimulating effect, β-glucans may participate in physiological processes related to the metabolism of fats in the human body. Their application results in a decrease in the total cholesterol content in blood and may also contribute to reductions in body weight.