White blood cells that are non-specific killers of microbes are

Options

A. B cells
B. neutrophils
C. killer T cells
D. helper T cells

Answer

To answer the question "White blood cells that are non-specific killers of microbes are:", we need to analyze the options provided:

1. **B cells**:
- B cells, also known as B lymphocytes, are primarily involved in the antibody-mediated immune response. They produce antibodies that specifically target pathogens. Therefore, B cells are considered specific killers of microbes, not non-specific.

2. **Neutrophils**:
- Neutrophils are a type of white blood cell that play a crucial role in the innate immune system. They are part of the body's first line of defense and are known for their ability to perform phagocytosis, which is the process of engulfing and destroying pathogens. Neutrophils act against a wide range of pathogens without the need for prior exposure, making them non-specific killers of microbes. Thus, this option is correct.

3. **Killer T cells**:
- Also known as cytotoxic T cells, killer T cells are specialized in recognizing and destroying infected or cancerous cells. They have the ability to distinguish between normal cells and abnormal cells, which makes them specific in their action. Therefore, killer T cells are not non-specific killers.

4. **Helper T cells**:
- Helper T cells assist in the activation of B cells and other T cells by presenting antigens. They are also specific in their function as they help target specific pathogens. Thus, helper T cells are not non-specific killers.

Based on this analysis, the correct answer to the question is **neutrophils**.

### Step-by-step Solution:
1. Identify the role of B cells: They produce antibodies and are specific killers.
2. Analyze neutrophils: They perform phagocytosis and are non-specific killers.
3. Evaluate killer T cells: They target specific infected or cancerous cells.
4. Assess helper T cells: They assist in immune responses and are specific.
5. Conclude that neutrophils are the non-specific killers of microbes.