Differential expression of SAP and EAT-2-binding leukocyte cell-surface molecules CD84, CD150 (SLAM), CD229 (Ly9) and...

Area of Science:

• Immunology
• Cell Biology

Background:

• The CD150 (SLAM) family comprises nine immunoglobulin superfamily proteins crucial for lymphocyte activation.
• Six family members (CD84, CD150, CD229, CD244, NTB-A, CS1) associate with adapter proteins like SLAM-associated protein (SAP).
• SAP mutations cause X-linked lymphoproliferative disease, highlighting the family's importance in immune function.

Purpose of the Study:

• To investigate the expression patterns of CD84, CD150, CD229, and CD244 on various leukocyte and lymphocyte subsets.
• To determine if these receptors are differentially expressed across hematopoietic cells.
• To explore the potential non-redundant functions of these receptors in immune regulation.

Main Methods:

• Flow cytometric analysis was employed to assess the expression of CD84, CD150, CD229, and CD244.
• Expression levels were quantified on diverse leukocyte and lymphocyte populations, including thymocytes, T cells, antigen-presenting cells, monocytes, dendritic cells, and natural killer cells.

Main Results:

• CD84 and CD150 were found on thymocytes, mature T cells, and antigen-presenting cells, with high expression on memory T cells.
• CD150 expression increased significantly post-activation and was absent on resting monocytes and immature dendritic cells.
• CD229 expression was limited to lymphocytes, while CD244 showed preferential expression on natural killer cells, CD8(+) effector cells, monocytes, basophils, and eosinophils.

Conclusions:

• This study reveals a broader distribution of CD84, CD150, CD229, and CD244 than previously reported.
• The differential expression of these receptors on hematopoietic cells suggests distinct, non-redundant roles.
• These findings indicate that CD150 family members play significant roles in regulating both innate and adaptive immunity.