NKG2D-dependent effector function of bronchial epithelium-activated alloreactive T-cells

Area of Science:

• Immunology
• Cell Biology
• Transplantation Science

Background:

• Allogeneic haematopoietic stem cell transplantation (SCT) is a curative therapy.
• The role of graft-versus-host disease in post-SCT lung injury remains unclear.

Purpose of the Study:

• Investigate immune responses of allogeneic CD8+ T-cells against respiratory epithelial cells.
• Determine the mechanisms of T-cell activation and cytotoxicity towards bronchial epithelial cells.

Main Methods:

• Utilized primary bronchial epithelial cells and the BEAS-2B cell line.
• Stimulated CD8+ T-cells with irradiated epithelial cells and assessed cytokine production, proliferation, and cytotoxicity.
• Performed phenotyping and inhibition experiments to elucidate effector mechanisms.

Main Results:

• CD8+ T-cells produced interferon-gamma and upregulated activation markers upon stimulation with epithelial cells.
• Induced bronchial epithelial cell-specific, granzyme B-mediated cytotoxicity in CD8+ T-cells.
• Demonstrated non-MHC-I restricted lysis dependent on NKGD signaling, excluding NK cell-derived populations.

Conclusions:

• Respiratory epithelium possesses antigen-presenting capabilities.
• Direct alloactivation of cytotoxic CD8+ T-cells by respiratory epithelium contributes to nonclassical effector functions.
• These findings suggest a novel mechanism for lung injury in graft-versus-host disease post-SCT.