Which of the following option about various types of antibodies is correct?

Options

A. The most abundant antibody is lgM and the antibody which is largest in size is lgG
B. The most abundant antibody is lgG and the antibody which is largest in size is lgM
C. lgA is the most abundant antibody as well as it appears as pentamer
D. IgG is the most abundant antibody found in colostrum , while lgE is found in the case of hypersensitivity

Answer

To determine which option about various types of antibodies is correct, we need to analyze the characteristics of the main classes of antibodies (immunoglobulins) in the human body.

### Step-by-Step Solution:

1. **Identify the Types of Antibodies**: The main types of antibodies are IgG, IgM, IgA, IgE, and IgD. Each type has different functions and characteristics.

2. **Determine the Most Abundant Antibody**:
- IgG is known to be the most abundant antibody in the bloodstream, making up about 75-80% of the total immunoglobulin pool.
- IgA is primarily found in mucosal areas and secretions, such as saliva and breast milk, but it is not the most abundant overall.

3. **Identify the Largest Antibody**:
- IgM is the largest antibody in terms of size and structure. It is a pentamer, meaning it consists of five antibody units joined together, allowing it to bind to multiple antigens simultaneously.
- IgG, on the other hand, is monomeric and smaller than IgM.

4. **Analyze the Options**:
- The statement claiming that "the most abundant antibody is IgM and the largest antibody is IgG" is incorrect.
- The statement that "the most abundant antibody is IgG and the largest is IgM" is correct.
- The statement that "IgA is the most abundant" is incorrect.
- The statement regarding IgE being related to hypersensitivity is true, but it does not address the abundance or size.

5. **Conclusion**: The correct option regarding the types of antibodies is that IgG is the most abundant antibody, and IgM is the largest antibody.

### Final Answer:
The correct statement is: The most abundant antibody is IgG, and the largest antibody is IgM.