Lung endothelial cell antigen cross-presentation to CD8(+)T cells drives malaria-associated lung injury

Malaria-associated acute respiratory distress syndrome (ARDS) and acute lung injury (ALI) are life-threatening manifestations of severe malaria infections. The pathogenic mechanisms that lead to respiratory complications, such as vascular leakage, remain unclear. Here, we confirm that depleting CD8(+)T cells with anti-CD8β antibodies in C57BL/6 mice infected with P. berghei ANKA (PbA) prevent pulmonary vascular leakage. When we transfer activated parasite-specific CD8(+)T cells into PbA-infected TCRβ(−/−) mice (devoid of all T-cell populations), pulmonary vascular leakage recapitulates. Additionally, we demonstrate that PbA-infected erythrocyte accumulation leads to lung endothelial cell cross-presentation of parasite antigen to CD8(+)T cells in an IFNγ−dependent manner. In conclusion, pulmonary vascular damage in ALI is a consequence of IFNγ-activated lung endothelial cells capturing, processing, and cross-presenting malaria parasite antigen to specific CD8(+)T cells induced during infection. The mechanistic understanding of the immunopathogenesis in malaria-associated ARDS and ALI provide the basis for development of adjunct treatments.