CpG DNA stimulates autoreactive immature B cells in the bone marrow

Area of Science:

• Immunology
• Cell Biology

Background:

• Developing B cells are typically nontolerant and express autoreactive receptors.
• CpG DNA is known to activate mature B cells, but its effect on developing B cells is not well understood.

Purpose of the Study:

• To investigate if developing B cells respond to CpG DNA stimulation.
• To determine if CpG DNA interferes with central tolerance in developing B cells.

Main Methods:

• Assessing B cell proliferation and differentiation following CpG DNA exposure.
• Utilizing in vitro, ex vivo, and in vivo models to study B cell selection and gene expression.
• Analyzing Toll-like receptor 9 (TLR9) expression on developing B cells.

Main Results:

• Developing B cells express TLR9 and mount a polyclonal response to CpG DNA, including proliferation and antibody production.
• CpG DNA stimulation protects immature B cells from negative selection (apoptosis and receptor editing) and promotes autoantibody generation.
• In vivo CpG DNA administration activates immature B cells in bone marrow and suppresses recombination-activating gene expression.

Conclusions:

• CpG DNA acts as a mitogen for nontolerant developing B cells in the bone marrow.
• CpG DNA stimulation has the potential to disrupt the establishment of central immune tolerance.