Which immunoglobulin is the least prevalent?

Options

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

Answer

To determine which immunoglobulin is the least prevalent, follow these steps:

1. **Identify the Types of Immunoglobulins**: There are five main types of immunoglobulins (Ig): IgA, IgD, IgE, IgG, and IgM. Each has different functions and prevalence in the body.

2. **Review the Prevalence of Each Immunoglobulin**:
- **IgA**: This immunoglobulin is primarily found in mucosal areas and is relatively abundant.
- **IgD**: This immunoglobulin is present in small amounts, primarily on the surface of B lymphocytes.
- **IgE**: This immunoglobulin is involved in allergic reactions and defense against parasites. It is known to be present in very low concentrations in the serum.
- **IgG**: This is the most abundant immunoglobulin in the serum and plays a key role in the immune response.

3. **Compare the Concentrations**: Among these immunoglobulins, IgE has a serum concentration that is approximately 10,000 times less than that of IgG, making it the least prevalent immunoglobulin.

4. **Conclusion**: Based on the information gathered, the immunoglobulin that is least prevalent in the body is IgE.

**Final Answer**: The least prevalent immunoglobulin is IgE (option number 3).

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