Helper T cells are distinguished from cytotoxic T-cells due to presence of

Options

A. `CD_(2)`
B. `CD_(4)`
C. `CD_(3)`
D. IL- 2 receptor

Answer

**Step-by-Step Solution:**

1. **Identify the Types of T Cells**:
- T cells are primarily classified into two types: Helper T cells (Th) and Cytotoxic T cells (Tc).

2. **Understand the Function of Each Type**:
- Helper T cells (Th) are responsible for activating other immune cells, such as B cells and T cells, by secreting cytokines.
- Cytotoxic T cells (Tc) are primarily involved in killing virus-infected cells and tumor cells.

3. **Recognize the Surface Markers**:
- Helper T cells are characterized by the presence of CD4 receptors on their surface.
- Cytotoxic T cells have CD8 receptors on their surface.

4. **Differentiate Based on Major Histocompatibility Complex (MHC)**:
- Helper T cells recognize antigens presented by MHC class II molecules, which are found on antigen-presenting cells like macrophages, B cells, and dendritic cells.
- Cytotoxic T cells recognize antigens presented by MHC class I molecules, which are present on all nucleated cells.

5. **Conclude the Distinguishing Feature**:
- The primary distinguishing feature between Helper T cells and Cytotoxic T cells is the presence of CD4 receptors on Helper T cells and CD8 receptors on Cytotoxic T cells.

6. **Final Answer**:
- Helper T cells are distinguished from cytotoxic T cells due to the presence of CD4 receptors.