Objective:

To ascertain whether nutrient deprivation induces CD3 expression in RAW macrophages and to identify the signaling molecules involved in the activation of a CD3-dependent proinflammatory profile.

Approach:

• Nutrient Deprivation Assessment: Evaluated the impact of nutrient deprivation on CD3 expression over time.
• Cell Stimulation: Stimulated RAW cells with anti-CD3 and IgG2a to assess proinflammatory cytokine profiles and signaling protein expression.
• Transcriptional Regulation Analysis: Examined the transcriptional regulation of IRF-1, GATA-3, and MAFB.
• Functional Capacity Testing: Determined the functional capacity of CD3+ RAW cells through a phagocytosis assay.

Key Findings:

• RAW cells expressed CD3, TCR, and CD4, with CD3 expression significantly upregulated at both the protein and transcriptional levels under nutrient deprivation.
• CD3+ RAW cells exhibited enhanced phagocytic activity.
• Stimulation with anti-CD3 plus IgG2a induced a robust proinflammatory cytokine response, including IFN-γ, TNF, and IL-6.
• The proinflammatory response was associated with activation of NFAT, c-Jun, and IKK signaling pathways, increased IRF-1 expression, and downregulation of MAFB.

Interpretation:

The study establishes RAW macrophages as a model for investigating CD3+ signaling in myeloid cells, demonstrating that nutrient deprivation induces CD3 expression and activates a CD3-dependent proinflammatory program.

Limitations:

• The study is based on a murine cell line, which may not fully replicate human macrophage behavior.
• The low prevalence of CD3+ macrophages in human samples limits direct translation of findings.

Conclusion:

Nutrient deprivation enhances CD3 expression in RAW macrophages and activates a proinflammatory response mediated by NFAT and IRF-1, providing insights into the functional significance of CD3+ macrophages.