Related Experiment Video
Updated: May 23, 2026
Retroviral Overexpression of CXCR4 on Murine B-1a Cells and Adoptive Transfer for Targeted B-1a Cell Migration to the Bone Marrow and IgM Production
Published on: May 31, 2020
Proper desensitization of CXCR4 is required for lymphocyte development and peripheral compartmentalization in mice
Karl Balabanian1, Emilie Brotin, Vincent Biajoux
1Inserm Unité Mixte de Recherche (UMR) S996, Université Paris-Sud, Laboratory of Excellence in Research on Medication and Innovative Therapeutics, Clamart, France. karl.balabanian@u-psud.fr
Abstract:
Desensitization controls G protein-dependent signaling of chemokine receptors. We investigate the physiologic implication of this process for CXCR4 in a mouse model harboring a heterozygous mutation of the Cxcr4 gene, which engenders a desensitization-resistant receptor. Such anomaly is linked to the warts, hypogammaglobulinemia, infections, myelokathexis (WHIM) syndrome, a human rare combined immunodeficiency. Cxcr4(+/mutant(1013)) mice display leukocytes with enhanced responses to Cxcl12 and exhibit leukopenia as reported in patients. Treatment with CXCL12/CXCR4 antagonists transiently reverses blood anomalies, further demonstrating the causal role of the mutant receptor in the leukopenia. Strikingly, neutropenia occurs in a context of normal bone marrow architecture and granulocyte lineage maturation, indicating a minor role for Cxcr4-dependent signaling in those processes. In contrast, Cxcr4(+/1013) mice show defective thymopoiesis and B-cell development, accounting for circulating lymphopenia. Concomitantly, mature T and B cells are abnormally compartmentalized in the periphery, with a reduction of primary follicles in the spleen and their absence in lymph nodes mirrored by an unfurling of the T-cell zone. These mice provide a model to decipher the role of CXCR4 desensitization in the homeostasis of B and T cells and to investigate which manifestations of patients with WHIM syndrome may be overcome by dampening the gain of CXCR4 function.
Insights
Desensitization resistance in the CXCR4 receptor causes WHIM syndrome by impairing immune cell development and distribution. Targeting CXCR4 function may offer therapeutic benefits for patients with this rare immunodeficiency.
Area of Science:
- Immunology
- Molecular Biology
- Genetics
Background:
- Chemokine receptor desensitization regulates G protein-dependent signaling.
- The CXCR4 receptor and its ligand CXCL12 play critical roles in immune cell trafficking and homeostasis.
- Mutations in CXCR4 are associated with Warts, Hypogammaglobulinemia, Infections, and Myelokathexis (WHIM) syndrome, a rare combined immunodeficiency.
Purpose of the Study:
- To investigate the physiological implications of CXCR4 desensitization resistance in a mouse model.
- To elucidate the role of CXCR4 signaling in immune cell development, distribution, and the pathogenesis of WHIM syndrome.
Main Methods:
- Generation and analysis of Cxcr4(+/mutant(1013)) mice with a heterozygous mutation conferring desensitization resistance.
- Assessment of leukocyte responses to CXCL12, blood cell counts, bone marrow cellularity, and immune cell development.
- Evaluation of T and B cell compartmentalization in lymphoid organs.
Main Results:
- Cxcr4(+/mutant(1013)) mice exhibited enhanced leukocyte responses to CXCL12 and developed leukopenia, mirroring WHIM syndrome patients.
- Neutropenia occurred despite normal bone marrow architecture and granulocyte maturation, suggesting limited CXCR4 role in these specific processes.
- Defective thymopoiesis and B-cell development led to lymphopenia, with abnormal peripheral T and B cell distribution and altered splenic and lymph node architecture.
Conclusions:
- CXCR4 desensitization resistance is a key factor in WHIM syndrome pathogenesis, primarily affecting T and B cell homeostasis.
- The mouse model provides a valuable tool for studying CXCR4's role in immune cell regulation and exploring therapeutic strategies for WHIM syndrome.
- Targeting aberrant CXCR4 gain-of-function may ameliorate specific clinical manifestations of WHIM syndrome.
