Mechanical Properties Affect Primary T Cell Activation in 3D Bioprinted Hydrogels

Area of Science:

• Biomaterials Engineering
• Immunology
• Cell Biology

Background:

• T cells are crucial for adaptive immunity against pathogens and cancer.
• Traditional 2D culture systems do not fully replicate the native T cell microenvironment, impacting activation studies.
• Cell-extracellular matrix (ECM) interactions significantly influence T cell function.

Purpose of the Study:

• To investigate T cell responses in 3D bioprinted matrices with varying stiffness.
• To compare T cell activation in 3D versus 2D culture systems.
• To assess the impact of matrix biomechanics on T cell activation and cytokine production.

Main Methods:

• Utilized digital light processing (DLP)-based 3D bioprinting with gelatin methacryloyl (GelMA) hydrogels.
• Fabricated hydrogels with pathophysiologically relevant stiffnesses mimicking lymph node tissue.
• Activated EL4 T cell lymphoma line and primary mouse T cells using phorbol myristate acetate (PMA) and ionomycin in 2D and 3D cultures.

Main Results:

• T cell responses differed between 2D and 3D cultures, particularly in stiff matrices.
• Viability of EL4 and primary mouse T cells was higher in soft (19.83 ± 2.36 kPa) compared to stiff (52.95 ± 1.36 kPa) 3D matrices.
• Interleukin-2 (IL-2) release was significantly higher in both soft (7.4-fold) and stiff (5.9-fold) 3D matrices compared to 2D cultures.

Conclusions:

• 3D bioprinted scaffolds can recapitulate T cell activation in an engineered lymphoid tissue-mimetic system.
• Matrix stiffness is a critical factor influencing T cell viability and function in 3D environments.
• This approach offers a platform for studying T cell behavior in infectious diseases, autoimmunity, and cancer.