Which of the following immunoglobulin (Ig) is present in colostrum?

Options

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

Explanation

**Step-by-Step Solution:**

1. **Understanding Colostrum**: Colostrum is the first milk produced by a nursing mother shortly after giving birth, typically within 24 to 48 hours. It is a thick, yellowish fluid rich in nutrients and antibodies.

2. **Identifying Immunoglobulins**: Immunoglobulins, or antibodies, are proteins produced by the immune system to help fight infections. There are several types of immunoglobulins, including IgA, IgG, IgM, and IgE.

3. **Determining the Immunoglobulin in Colostrum**: Among the various immunoglobulins, IgA is specifically known to be present in colostrum. It plays a crucial role in mucosal immunity, protecting the newborn's gut from infections.

4. **Analyzing the Options**:
- **Option 1: IgA** - Present in colostrum.
- **Option 2: IgG** - Found in blood, lymph, and intestines, but not in colostrum.
- **Option 3: IgM** - Also found in blood and lymph, but not in colostrum.
- **Option 4: IgE** - Present in mast cells and basophils, not in colostrum.

5. **Conclusion**: Based on the analysis, the only immunoglobulin present in colostrum is **IgA**. Therefore, the correct answer is **Option 1: IgA**.

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