Which of the following cells are involved in immune mechanism of the body?

Options

A. lymphocytes
B. macrophages
C. neutrophils
D. All

Answer

To answer the question "Which of the following cells are involved in the immune mechanism of the body?", we need to identify the specific types of cells that play a role in the immune response.

### Step-by-Step Solution:

1. **Identify the Types of Cells**: The question provides options that include lymphocytes, macrophages, and neutrophils. We need to evaluate each of these cell types to determine their involvement in the immune mechanism.

2. **Lymphocytes**:
- Lymphocytes are a type of white blood cell that are crucial for the adaptive immune response.
- There are three main types of lymphocytes:
- **T lymphocytes (T cells)**: These are involved in cell-mediated immunity and are produced in the thymus.
- **B lymphocytes (B cells)**: These are responsible for humoral immunity and produce antibodies. They mature in the bone marrow.
- **Natural Killer (NK) cells**: These are involved in the innate immune response and can kill virus-infected cells.

3. **Macrophages**:
- Macrophages are large phagocytic cells that are part of the innate immune system. They engulf and digest pathogens and also play a role in activating T cells by presenting antigens.

4. **Neutrophils**:
- Neutrophils are another type of white blood cell that are part of the innate immune response. They are the first responders to sites of infection and play a key role in the inflammatory response.

5. **Conclusion**: All three types of cells mentioned (lymphocytes, macrophages, and neutrophils) are involved in the immune mechanism of the body. Therefore, the correct answer includes all of these cell types.

### Final Answer:
The cells involved in the immune mechanism of the body are lymphocytes, macrophages, and neutrophils.

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