MHC-II is present on :

Options

A. Macrophage
B. B-lymphocytes
C. Dendritic cells
D. All of the above

Answer

**Step-by-Step Solution:**

1. **Understanding MHC**: The question refers to MHC-II, which stands for Major Histocompatibility Complex class II. It is important to know what MHC molecules are and their function in the immune system.

2. **Identifying Antigen-Presenting Cells (APCs)**: MHC-II molecules are primarily found on the surface of antigen-presenting cells (APCs). These cells play a crucial role in the immune response by presenting antigens to T-helper cells.

3. **Types of APCs**: The main types of APCs that express MHC-II include:
- **Dendritic Cells**: These are professional APCs that are very efficient in presenting antigens to T cells.
- **Macrophages**: These are also mononuclear phagocytes that can present antigens and express MHC-II.
- **B-Lymphocytes**: These cells can present antigens to T cells and also express MHC-II molecules.

4. **Analyzing the Options**: The question provides multiple options:
- Option A: Macrophages
- Option B: B-lymphocytes
- Option C: Dendritic cells
- Option D: All of the above

5. **Conclusion**: Since MHC-II is present on all of the listed cell types (macrophages, B-lymphocytes, and dendritic cells), the correct answer is option D: all of the above.

**Final Answer**: MHC-II is present on all of the above (macrophages, B-lymphocytes, and dendritic cells).

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