C-Type Lectin-like Receptor LOX-1 Promotes Dendritic Cell-Mediated Class-Switched B Cell Responses

• LOX-1 programs B cells to upregulate CCR7
• LOX-1 programs DCs to promote class-switched antibody responses
• LOX-1 programs DCs to upregulate CCR10 expression on plasmablasts
• LOX-1 signaling on B cells and DCs combined promotes humoral responses

SummaryLectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is a pattern-recognition receptor for a variety of endogenous and exogenous ligands. However, LOX-1 function in the host immune response is not fully understood. Here, we report that LOX-1 expressed on dendritic cells (DCs) and B cells promotes humoral responses. On B cells LOX-1 signaling upregulated CCR7, promoting cellular migration toward lymphoid tissues. LOX-1 signaling on DCs licensed the cells to promote B cell differentiation into class-switched plasmablasts and led to downregulation of chemokine receptor CXCR5 and upregulation of chemokine receptor CCR10 on plasmablasts, enabling their exit from germinal centers and migration toward local mucosa and skin. Finally, we found that targeting influenza hemagglutinin 1 (HA1) subunit to LOX-1 elicited HA1-specific protective antibody responses in rhesus macaques. Thus, LOX-1 expressed on B cells and DC cells has complementary functions to promote humoral immune responses.