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Edema Factor

Although infection with the edema factor (EF) is not primary cause does not lead to death, it does promote severe tissue swelling at the site of infection. For inhalational anthrax, pulmonary edema and mediastinal widening caused by influx of macrophages in the chest lymph nodes further complicates the infection. EF has been characterized to have adenylyl cyclase activity and can be activated by calmodulin after entry into the macrophage. This leads to increased levels of cAMP, on top of the level normally produced, and results in misregulation of cytokines associated with edema. Macrophages infected by EF are induced to produce more IL-6, a cytokine which stimulates production of acute phase proteins by hepatocytes. Acute phase proteins are responsible for the systemic effects of bacterial infections and give rise to fevers because of the increased production of prostaglandins. EF has been shown to inhibit the production of TNF-a , which are involved with the recruitment of cellular immune cells to sites of infection (9). Together the two factors prevent the activation of the immune system and allows the organism to flourish.

Ribbon Model of Edema Factor (2)