Figure 5.

Hypothesized model of the proteasomal processing and major histocompatibility complex (MHC) class I presentation of cytosolic secreted T4SS effector proteins. According to our hypothesized model, some of the secreted Coxiella burnetii T4SS effector proteins were degraded by the proteasomal degradation pathway and presented by MHC class I molecules on the surface of infected cells, which enable recognition by antigen-specific CD8⁺ T cells. These secreted antigens may provide a novel set of vaccine candidates to induce anti–C. burnetii CD8⁺ T-cell immunity. Abbreviations: ER, endoplasmic reticulum; TAP, transporter associated with antigen processing.