Wild-derived mouse strains, a valuable model to study B cell responses.

Area of Science:

• Immunology
• Cell Biology

Background:

• Toll-like receptors (TLR) are crucial for immune responses.
• Wild-derived mouse strains offer unique genetic variations for studying immune function.

Purpose of the Study:

• To investigate B cell responsiveness to TLR ligands in wild-derived mouse strains.
• To identify strain-specific defects in B cell signaling pathways.

Main Methods:

• Testing B cell and macrophage responses to various TLR ligands (TLR-L) in 7 wild-derived mouse strains.
• Analyzing B cell proliferation, cytokine production, and antibody responses.
• Investigating intracellular signaling pathways (ERK, P38, JNK) in response to TLR4 and TLR9 stimulation.

Main Results:

• PWK and STF strains exhibited significant defects in B cell proliferation to most TLR-L, while macrophage responses remained largely normal.
• Anti-CD40 monoclonal antibodies (mAbs) rescued CpG-induced proliferation in PWK and STF B cells.
• STF B cells showed synergistic proliferation with CpG and lipopolysaccharide (LPS), despite unresponsiveness to LPS alone.
• In vitro cytokine and immunoglobulin (Ig) production were less impaired than proliferation.
• ERK, P38, and JNK pathways were affected in STF B cells upon TLR4/TLR9 signaling.
• In vivo antibody responses to T-independent (TI) and T-dependent (TD) antigens were severely impaired, particularly in STF mice.

Conclusions:

• Wild-derived mouse strains, like PWK and STF, reveal critical insights into B cell physiology and TLR pathway regulation.
• Distinct TLR pathway regulation exists between B cells and macrophages.
• Impaired B cell responses in these strains significantly affect adaptive antibody production.