Cell-specific MHC class I deletion on CD11c+APCs abrogates CD8 T Cell infiltration into the brain

Abstract Cerebral malaria (CM) is a severe complication of P. falciparum infection and a leading cause of death, globally. Plasmodium berghei ANKA (PbA) infection of C57BL/6 mice serves as a murine model of CM called experimental cerebral malaria (ECM) due to the neurological and neuropathological features that simulate the infection of human CM. A putative mechanism of disease in human CM requires CD8 T cell to infiltration into the brain and blood-brain barrier disruption. The specific antigen-presenting cell type(s) that prime this CNS infiltrating CD8 T cell response capable of inducing lethal blood-brain barrier disruption has not been defined. To answer this, single class I expressing K bloxP transgenic mice were generated. Crossing these mice to class I deficient CD11c-cre or LysM-cre mice created the LysM-cre K bcKO and CD11c-cre K bcKO mice, respectively. PbA infected K bloxP and LysM-cre K bcKO were susceptible to ECM. In contrast, CD11c-cre K bcKO mice survived acute PbA infection and avoided neurological manifestations. We therefore employed spectral flow cytometry to analyze splenocytes and brain infiltrating immune cells during acute PbA infection in these genotypes. We observed a reduction in activated CD8 T cells in the spleens of PbA infected CD11c-cre K bcKO mice versus the K bloxP mice and the LysM-cre K bcKO. This reduced peripheral CD8 T cell activation in PbA infected CD11c-cre Kb cKO mice also corresponded with reduced brain infiltration of CD8 T cells. We conclude a CD11c+ APC is therefore required for priming and potentially recruitment of CD8 T cells to the brain during lethal ECM pathology. 5R01NS103212-06