Evolution of self-reactive B cells: lessons from a lupus model

Area of Science:

• Immunology
• Autoimmunity
• B cell biology

Background:

• Systemic lupus erythematosus (SLE) is characterized by autoreactive B cells and an evolving autoantibody repertoire.
• B cell tolerance checkpoints can fail, leading to pathogenic autoantibody production.
• Epitope spreading describes the broadening of autoimmune responses over time.

Purpose of the Study:

• To review insights from the 564Igi lupus model regarding B cell recruitment and autoantibody evolution.
• To explore how an established autoreactive environment influences previously tolerant B cells.
• To reframe epitope spreading as a dynamic process of B cell evolution within autoimmune niches.

Main Methods:

• Utilized the 564Igi lupus model, which features a defined autoreactive B cell clone.
• Employed mixed bone marrow chimera and adoptive transfer techniques.
• Analyzed the recruitment and participation of wild-type (WT) B cells in autoimmune pathways.

Main Results:

• WT-derived B cells were recruited into established autoreactive niches.
• These recruited B cells participated in germinal center and extrafollicular pathways.
• WT B cells contributed to epitope-spread autoantibody responses, demonstrating B cell evolution.

Conclusions:

• The 564Igi model demonstrates that an autoimmune environment can incorporate previously tolerant B cells.
• Epitope spreading is a dynamic process where B cells evolve within supportive autoimmune niches.
• This reframes self-reactive B cell evolution and its contribution to sustained autoantibody responses in lupus.