Interferon-gamma is essential for the development of cerebral malaria

Infection with Plasmodium berghei ANKA (PbA) causes fatal cerebral malaria (CM). While a pathogenic role for tumor necrosis factor (TNF) has been established, we asked whether a disruption of interferon-gamma (IFN-gamma) signaling would modulate CM. We demonstrate here that IFN-gammaR-deficient mice are completely protected from CM. PbA-induced release of TNF and up-regulation of endothelial intercellular adhesion molecule (ICAM)-1 expression, recruitment of mononuclear cells, and cerebral microvascular damage with vascular leakage occur only in wild-type mice. Protected mice die at a later time of severe anemia and overwhelming parasitemia. Resistance to CM in IFN-gammaR-deficient mice is associated with reduced serum TNF levels, reduced interleukin-12 expression in the brain and increased T-helper 2 cytokines. In conclusion, IFN-gamma is apparently required for PbA-induced endothelial ICAM-1 up-regulation and subsequent microvascular pathology, resulting in fatal CM. In the absence of IFN-gamma signaling, ICAM-1 and TNF up-regulation is reduced; hence, PbA infection fails to cause fatal CM.