The function of IgE is:

Options

A. activation of B-cells
B. mediate in allergic response
C. present on lymphocytes surface as receptors
D. protection from inhaled and ingested pathogens

Answer

To answer the question about the function of IgE, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Types of Immunoglobulins**:
- There are different types of immunoglobulins (Ig), each with specific functions. The main types include IgA, IgD, IgE, IgG, and IgM.

2. **Analyze Each Option**:
- **Option 1: Activation of B cells**: This function is primarily associated with IgD, not IgE.
- **Option 2: Mediate in allergic response**: This is a known function of IgE, as it plays a crucial role in allergic reactions.
- **Option 3: Present on lymphocyte surface as a receptor**: This is the function of IgM, which acts as a receptor on B cells.
- **Option 4: Protection from inhaled pathogens**: This function is mainly performed by IgA, which protects mucosal surfaces.

3. **Identify the Correct Function of IgE**:
- From the analysis, it is clear that the primary function of IgE is to mediate allergic responses. This includes reactions such as hay fever, asthma, and anaphylaxis.

4. **Conclusion**:
- Therefore, the correct answer to the question "The function of IgE is:" is that it mediates allergic responses.

### Final Answer:
The function of IgE is to mediate allergic responses.

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