Which antibody is excreted through faeces ?

Options

A. IgG
B. IgA
C. IgM
D. both 1 and 2

Answer

To answer the question "Which antibody is excreted through faeces?", we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Antibodies**: The two main types of antibodies that are present in the human body are Immunoglobulin A (IgA) and Immunoglobulin G (IgG).

2. **Understand Their Role**: IgA is primarily found in mucosal areas, such as the intestines, and plays a crucial role in mucosal immunity. IgG, on the other hand, is the most abundant antibody in the blood and extracellular fluid, providing the majority of antibody-based immunity against invading pathogens.

3. **Excretion through Faeces**: Among these antibodies, IgA is specifically known to be secreted in high amounts in mucosal secretions, including saliva, tears, and intestinal secretions. Therefore, it is predominantly found in faeces.

4. **Confirm the Presence in Faeces**: Both IgA and IgG can be detected in faeces, but IgA is the primary antibody associated with mucosal immunity and is more commonly excreted through faeces.

5. **Conclusion**: Based on the above points, the antibody that is primarily excreted through faeces is Immunoglobulin A (IgA).

### Final Answer:
The antibody that is excreted through faeces is Immunoglobulin A (IgA).