Which one of the following immune system components does not correctly match with its respective role ?

Options

A. Interferons - secreted by virus-infected cells and protect non-infected cells from further viral infection.
B. B- lymphocytes - produce antibodies in response to pathogens into blood to fight with them.
C. Macrophages - mucus secreting cells that trap microbes entering in the body.
D. IgA - present in colostrum in early days lactation to protect infant from diseases.

Explanation

To solve the question regarding which immune system component does not correctly match with its respective role, we will analyze each option provided.

### Step-by-Step Solution:

1. **Interferons**:
- **Role**: Secreted by virus-infected cells to protect non-infected cells from further viral infection.
- **Explanation**: Interferons are signaling proteins released in response to viral infections. They help neighboring cells enhance their antiviral defenses.
- **Conclusion**: This statement is correct.

2. **Lymphocytes (B Lymphocytes)**:
- **Role**: Produce antibodies in response to pathogens in the blood to fight them.
- **Explanation**: B lymphocytes, a type of white blood cell, are responsible for producing antibodies that target specific pathogens.
- **Conclusion**: This statement is also correct.

3. **Macrophages**:
- **Role**: Mucus-secreting cells that trap microbes entering the body.
- **Explanation**: This is incorrect. Macrophages are large phagocytic cells that engulf and digest foreign substances, such as bacteria and dead cells. They do not secrete mucus.
- **Conclusion**: This statement is incorrect.

4. **IgA (Immunoglobulin A)**:
- **Role**: Present in colostrum during early lactation to protect infants from diseases.
- **Explanation**: IgA is indeed found in colostrum and plays a crucial role in providing passive immunity to newborns.
- **Conclusion**: This statement is correct.

### Final Answer:
The immune system component that does not correctly match with its respective role is **macrophages**, as they are not mucus-secreting cells but rather phagocytic cells that engulf pathogens.

---