From the listed markers, which is a T-cell marker?

From the listed markers, which is a T-cell marker?

• A. CD19
• B. CD20
• C. CD3
• D. CD34

Answer: (C)

The thing being tested is how we identify what type of immune cell we’re looking at using specific surface markers in immunohistochemistry. A T-cell marker is CD3. CD3 forms part of the T-cell receptor complex and is present on nearly all mature T cells, making it a universal (pan-) marker for T cells in tissue samples. That’s why staining for CD3 highlights T cells. In contrast, CD19 and CD20 are markers for B lymphocytes, tagging B cells instead of T cells. CD34 marks hematopoietic progenitor cells (and sometimes endothelial cells) rather than mature T cells. So CD3 is the best choice to identify T cells.

The thing being tested is how we identify what type of immune cell we’re looking at using specific surface markers in immunohistochemistry. A T-cell marker is CD3. CD3 forms part of the T-cell receptor complex and is present on nearly all mature T cells, making it a universal (pan-) marker for T cells in tissue samples. That’s why staining for CD3 highlights T cells.

In contrast, CD19 and CD20 are markers for B lymphocytes, tagging B cells instead of T cells. CD34 marks hematopoietic progenitor cells (and sometimes endothelial cells) rather than mature T cells. So CD3 is the best choice to identify T cells.