Related Experiment Video
Updated: Jul 11, 2026
A Detailed Protocol for Characterizing the Murine C1498 Cell Line and its Associated Leukemia Mouse Model
Published on: October 14, 2016
Characterization of mouse CD229 (Ly9), a leukocyte cell surface molecule of the CD150 (SLAM) family
J Sintes1, M Vidal-Laliena, X Romero
1Immunology Unit, Department of Cellular Biology and Pathology, Medical School, University of Barcelona, Barcelona, Spain.
Insights
Mouse CD229 (Ly9), a leukocyte activation molecule, is expressed on most lymphocytes and monocytes. Ligation of CD229 inhibits T-cell activation and cytokine production, suggesting its role in immune regulation.
Area of Science:
- Immunology
- Cell Biology
Background:
- CD229 (Ly9) is a cell surface molecule within the CD150 signaling lymphocyte activation molecule (SLAM) family.
- The SLAM family comprises nine immunoglobulin superfamily receptors crucial for leukocyte activation.
- CD229 interacts with SAP, a protein linked to X-linked lymphoproliferative disease.
Purpose of the Study:
- To characterize the expression pattern of mouse CD229 on various hematopoietic cells.
- To investigate the functional role of CD229 in T-lymphocyte activation.
Main Methods:
- Development and use of a novel CD229-specific monoclonal antibody (mAb), Ly9.ab3.
- Flow cytometry to assess CD229 expression on hematopoietic stem cells, lymphocytes, monocytes, and other cell types.
- In vitro functional assays to evaluate the effect of CD229 ligation on T-cell activation markers and cytokine production.
Main Results:
- CD229 is expressed on hematopoietic stem cells and increases during lymphocyte maturation.
- High CD229 expression is found on T cells, B cells, natural killer (NK) cells, NK T cells, and B1 cells.
- CD229 is also expressed on monocytes, but absent on granulocytes, dendritic cells, platelets, and red blood cells.
- Ligation of CD229 inhibits T-lymphocyte expression of activation markers (CD69, CD25) and reduces cytokine production.
Conclusions:
- CD229 serves as a pan-lymphocyte marker in mice.
- Monoclonal antibodies targeting CD229 can down-modulate T-cell activation, indicating a potential therapeutic target.
Abstract:
Mouse CD229 (Ly9) is a cell surface molecule of the CD150 (signaling lymphocyte activation molecule) family. This family consists of nine leukocyte receptors of the immunoglobulin superfamily that are involved in leukocyte activation. CD229 binds to SAP, a protein encoded by the gene for X-linked lymphoproliferative disease. In this study, mouse CD229 expression was assessed with a new CD229-specific monoclonal antibody (mAb) (Ly9.ab3), raised using CD229-transfected cells. CD229 was expressed on Sca-1+c-kit+Lin- hematopoietic stem cells, and this expression increased during lymphocyte maturation. Virtually, all T and B cells expressed high levels of CD229. CD229 was absent on granulocytes, bone marrow-derived dendritic cells, platelets, and red blood cells (RBCs). However, it was expressed at significant levels on monocytes, indicating that it is also expressed on mouse myeloid cells. We also show that natural killer cells, natural killer T cells, and B1 cells express very high levels of this molecule. In vitro functional experiments showed that ligation of CD229 inhibited the expression of the activation markers CD69 and CD25 on T lymphocytes in response to anti-CD3 stimulation. Moreover, this reduced activation was concurrent with a reduction in cytokine production. Our results show that CD229 is a pan-lymphocyte marker and indicate that mAbs against CD229 are able to down-modulate T-cell activation.
