The Chytrid Fungus Paralyzes Lymphocyte Responses

A new paper in Science describes a mechanism that may explain why Bd is such a deadly pathogen. The abstract of the paper (click here to read the paper on the Science website

): "The chytrid fungus, Batrachochytrium dendrobatidis, causes chytridiomycosis and is a major contributor to global amphibian declines. Although amphibians have robust immune defenses, clearance of this pathogen is impaired. Because inhibition of host immunity is a common survival strategy of pathogenic fungi, we hypothesized that B. dendrobatidis evades clearance by inhibiting immune functions. We found that B. dendrobatidis cells and supernatants impaired lymphocyte proliferation and induced apoptosis; however, fungal recognition and phagocytosis by macrophages and neutrophils was not impaired. Fungal inhibitory factors were resistant to heat, acid, and protease. Their production was absent in zoospores and reduced by nikkomycin Z, suggesting that they may be components of the cell wall. Evasion of host immunity may explain why this pathogen has devastated amphibian populations worldwide." There is also a podcast interview: http://www.sciencemag.org/content/342/6156/366/suppl/DC2