Two recently published articles confirm the immune actions of Agaricus blazei Murill against viruses. The Agaricus blazei Murill (ABM) mushroom, known as the “Sun Mushroom” and as “Cogmelo de Deus” (“Mushroom of God”), is native to Brazil and has become known for its medicinal properties. ABPC (Agaricus Blazei Practical Compound), which is the mushroom treated by digestive enzyme offered by Obiken, can be found in the Physician’s Desk Reference (PDR) https://dosetherapy.org/ .
An extract of Agaricus blazei Murill protected against systemic Streptococcus pneumoniae 6B infection in the mice. The authors concluded that these results suggest that Agaricus blazei Murill extract may be useful as additional prophylactic and possibly therapeutic treatment against bacterial and possibly other infections in humans. 
Co-administration of an extract of Agaricus blazei Murill with foot-and-mouth disease virus antibody increased the specific immune response against the virus and T cell proliferation in mice. 
Agaricus blazei Murill is rich in polysaccharides, such as beta-glucan, which have been shown to vitalize the immune system. The beta-glucans have been shown to have potent anti-tumor activity in mice. Beta(1-3)D-glucan, such as schizophyllan, has been used clinically in cancer therapy in Japan.
1. Bernardshaw, S., E. Johnson, and G. Hetland, An Extract of the Mushroom Agaricus blazei Murill Administered Orally Protects Against Systemic Streptococcus pneumoniae Infection in Mice. Scand J Immunol, 2005. 62(4): p. 393-8.