Virally infected mouse liver endothelial cells trigger CD8+ T-cell immunity

Area of Science:

• Immunology
• Cell Biology
• T-cell Activation

Background:

• Dendritic cell activation via pattern recognition receptors (PRRs) typically induces CD8(+) T-cell immunity.
• Organ-resident antigen-presenting cells (APCs), like liver sinusoidal endothelial cells (LSECs), are investigated for their role in immune tolerance or activation.

Purpose of the Study:

• To determine if LSECs can switch from tolerogenic to immunogenic APCs upon stimulation.
• To investigate the role of LSECs in CD8(+) T-cell activation.

Main Methods:

• Murine LSECs were isolated and analyzed for functional maturation after PRR triggering or viral infection.
• Gene expression analysis and T-cell coculture assays were employed.
• In vivo relevance was assessed using bone-marrow chimeric mice.

Main Results:

• LSECs express PRRs but ligand-induced activation was insufficient to overcome CD8(+) T-cell tolerance.
• Murine cytomegalovirus infection induced LSEC maturation and promoted antigen-specific effector CD8(+) T-cell differentiation.
• This LSEC-mediated T-cell activation occurred independently of dendritic cells and CD80/86 costimulatory molecules.

Conclusions:

• LSECs can mature and induce CD8(+) T-cell immunity, particularly upon viral infection.
• These findings offer insights into organ-specific immunity and overcoming immune tolerance in contexts like cancer.