Question

Which of these cells is CD8 positive cell?

• A. Macrophage
• B. Neutrophil
• C. T suppressor cell
• D. T helper cell

Hint:

Remember the classic T-cell subdivisions:
- Helper T cells = \(\text{CD4}^+\) (Interact with MHC II).
- Cytotoxic Suppressor T cells = \(\text{CD8}^+\) (Interact with MHC I).

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Cluster of Differentiation (CD) molecules are specific cell-surface glycoproteins used to identify and immunophenotype distinct leukocyte subpopulations.

Step 2: Detailed Explanation:
1. CD8 is a transmembrane glycoprotein co-receptor that is characteristically expressed on the surface of:
- Cytotoxic T-lymphocytes (\(\text{T}_{\text{c}}\) cells)
- T suppressor cells
These \(\text{CD8}^+\) cells interact specifically with MHC Class I molecules to recognize and kill intracellular pathogens or regulate immune responses.
2. T helper cells (D) express the CD4 glycoprotein, interacting with MHC Class II.
3. Macrophages (A) and Neutrophils (B) are myeloid-lineage phagocytes and do not express CD8.
Therefore, the T suppressor cell is a CD8 positive cell.

Step 3: Final Answer:
The correct option is 3, which corresponds to T suppressor cell.