The 1A4 molecule (CD27) is involved in T cell activation

Area of Science:

• Immunology
• Molecular Biology

Background:

• The CD27 molecule is implicated in T cell activation, but direct evidence of its role in the activation process is limited.
• Existing anti-CD27 monoclonal antibodies (mAbs) recognize epitopes distinct from the novel anti-1A4 mAb.

Purpose of the Study:

• To investigate the role of the CD27 molecule in T cell activation using a newly developed mAb, anti-1A4.
• To determine the functional consequences of anti-1A4 binding to CD27 on T and B cell responses.

Main Methods:

• Development of a novel mAb, anti-1A4, targeting a distinct CD27 epitope.
• Assays to measure T cell proliferation induced by anti-CD2, anti-CD3, mitogens, or soluble antigens.
• Assessment of B cell immunoglobulin G (IgG) synthesis.
• Measurement of Interleukin-2 (IL-2) secretion and IL-2 receptor (IL-2R) expression.
• Analysis of intracellular calcium mobilization in T cells.

Main Results:

• Anti-1A4 significantly inhibited T cell proliferation induced by various stimuli.
• Anti-1A4 suppressed T cell-dependent B cell IgG synthesis.
• IL-2 secretion was inhibited by anti-1A4, while IL-2R expression remained unaffected.
• Pretreatment with anti-1A4 blocked sustained intracellular calcium mobilization following CD2 or CD3 pathway activation.
• Binding of anti-1A4 to CD27 demonstrated a negative regulatory effect on T cell activation.

Conclusions:

• The CD27 molecule plays an integral role in T cell activation.
• Anti-1A4 binding to CD27 negatively impacts T cell activation, potentially through direct signaling or blocking cell interactions.
• These findings provide direct evidence for CD27's involvement in regulating immune responses.