Depleting Autoreactive B‑Cells Using Targeted Photodynamic Therapy.

Area of Science:

• Immunology
• Biotechnology
• Photomedicine

Background:

• Autoimmune diseases like Rheumatoid Arthritis (RA) involve autoreactive B cells driving pathology.
• Current B cell-depleting therapies lack specificity, causing broad immune deficiency.

Purpose of the Study:

• To develop a targeted therapy to selectively eliminate autoreactive B cells.
• To investigate the efficacy of targeted photodynamic therapy (tPDT) for this purpose.

Main Methods:

• Designed a construct with a dimeric peptidic antigen (diCCP4) targeting a specific autoreactive B cell receptor (BCR).
• Incorporated the photosensitizer IRDye700DX into the construct.
• Tested the construct on a modified Ramos B-cell line expressing the target BCR.
• Evaluated cell viability after light exposure in a 3D coculture with peripheral blood mononuclear cells (PBMCs).

Main Results:

• The tPDT construct selectively eliminated modified Ramos B cells expressing the autoreactive BCR upon light activation.
• The construct showed no cytotoxicity to cells lacking the target BCR.
• Coculture experiments demonstrated minimal impact on untargeted cells.

Conclusions:

• Targeted photodynamic therapy (tPDT) effectively and selectively eliminates autoreactive B cells.
• This approach holds potential for treating autoimmune diseases like RA with reduced side effects.
• Further research is warranted to translate this therapy to clinical applications.