An antibody present in colostrum is

Options

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

Answer

To solve the question "An antibody present in colostrum is," we will analyze the options provided and determine which antibody is predominantly found in colostrum.

### Step-by-Step Solution:

1. **Understanding Colostrum**:
- Colostrum is the first milk produced by a mother after giving birth. It is rich in antibodies and nutrients, providing essential immune protection to the newborn.

2. **Identifying Antibodies**:
- The question provides four options for antibodies: IgG, IgA, IgM, and IgD. We need to identify which of these is primarily found in colostrum.

3. **Analyzing Each Antibody**:
- **IgG (Immunoglobulin G)**: This is the most abundant antibody in the blood and extracellular fluid, providing the majority of antibody-based immunity against invading pathogens. However, it is not the primary antibody in colostrum.
- **IgA (Immunoglobulin A)**: This antibody is found in mucosal areas, such as the gut, respiratory tract, and urogenital tract, as well as in secretions like saliva, tears, and breast milk. It plays a crucial role in mucosal immunity and is the predominant antibody in colostrum.
- **IgM (Immunoglobulin M)**: This is the first antibody produced in response to an infection and is primarily found in blood and lymphatic fluid. It is not the main antibody in colostrum.
- **IgD (Immunoglobulin D)**: This antibody is present in small amounts in the blood and is primarily found on the surface of immature B lymphocytes. It does not play a significant role in colostrum.

4. **Conclusion**:
- Based on the analysis, the antibody that is predominantly present in colostrum is **IgA**.

### Final Answer:
The antibody present in colostrum is **IgA**.