Which Ig is produced in primary immune response
or
Which antibody is first to be released into blood following an infection

Options

A. IgA
B. IgE
C. IgG
D. IgM

Answer

**Step-by-Step Solution:**

1. **Understanding the Immune Response**: The immune system has a primary response and a secondary response. The primary immune response occurs when the body is first exposed to a pathogen.

2. **Identifying the Antibodies**: There are several types of immunoglobulins (Ig), including IgA, IgE, IgG, and IgM. Each type has a specific role in the immune response.

3. **Role of IgA**: IgA is primarily found in mucosal areas, such as saliva and tears, and acts as a first line of defense against pathogens entering through mucosal surfaces.

4. **Role of IgE**: IgE is mainly involved in allergic reactions and protection against parasitic infections. It is found in the lungs and mucous membranes.

5. **Role of IgG**: IgG is the most abundant antibody in the blood and plays a crucial role in neutralizing pathogens. It is produced later in the immune response and is important for long-term immunity.

6. **Role of IgM**: IgM is the largest antibody and is produced first in response to an infection. It is found in blood and lymph fluid and is the first type of antibody made when the body encounters a new pathogen.

7. **Conclusion**: Since IgM is the first antibody produced during the primary immune response, the answer to the question is that IgM is the immunoglobulin produced in the primary immune response and is the first antibody released into the blood following an infection.

**Final Answer**: The immunoglobulin produced in the primary immune response is **IgM**.

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