B-cell activating factor (BAFF) promotes CpG ODN-induced B cell activation and proliferation
Rachelle M Buchanan1, Yurij Popowych, Natasha Arsic
1Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatchewan, Canada.
Cellular Immunology
|July 5, 2011
Summary
Naïve B cells require co-stimulation from myeloid cells and BAFF for direct activation by toll-like receptor 9 (TLR9) ligand, CpG ODN. This finding is crucial for understanding B cell activation and autoimmune diseases.
Area of Science:
- Immunology
- Cell Biology
Background:
- The direct activation of naïve B cells by toll-like receptor 9 (TLR9) ligand, CpG oligodeoxynucleotides (ODN), remains controversial.
- Bovine CD21(+) B cells express TLR9 and show some proliferation to CpG in mixed populations, but purified B cells do not activate significantly, even with B cell receptor engagement.
Purpose of the Study:
- To investigate the requirements for CpG-ODN-induced activation of bovine naïve B cells.
- To determine the role of myeloid cells and B-cell activating factor (BAFF) in enhancing B cell responses to TLR9 ligands.
Main Methods:
- Purified bovine B cells were co-cultured with CD14(+) myeloid cells and/or BAFF.
- B cell proliferation and activation markers (e.g., CD25, large cell size) were assessed following CpG-ODN stimulation.
Main Results:
- Purified B cells showed significantly increased CpG-ODN-specific proliferation when co-cultured with myeloid cells and/or BAFF.
- Co-culture conditions also led to an increase in B cells expressing activation markers like CD25 and larger cell morphology.
Conclusions:
- Activated myeloid cells and BAFF are essential for priming B cells to respond effectively to CpG-ODN.
- These findings highlight the importance of cellular interactions and cytokine support for TLR9-mediated B cell activation, with implications for understanding autoimmune diseases and polyclonal B cell activation.
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