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 solve the question regarding the correct statements about various types of antibodies, we will analyze each option step by step.

### Step 1: Understand the Types of Antibodies
Antibodies, also known as immunoglobulins, are proteins produced by the immune system to identify and neutralize pathogens. There are five main types of antibodies: IgG, IgM, IgA, IgD, and IgE.

### Step 2: Analyze Each Option
1. **First Option**: "Most abundant antibody is IgM and antibody which is largest in size is IgG."
- **Analysis**: This statement is incorrect. The most abundant antibody in the blood is IgG, not IgM. IgM is the largest antibody in terms of size (it is a pentamer), while IgG is smaller in size.

2. **Second Option**: "Most abundant antibody is IgG and largest size is IgM."
- **Analysis**: This statement is correct. IgG is indeed the most abundant antibody in the blood, and IgM is the largest antibody due to its pentameric structure.

3. **Third Option**: "IgA is the most abundant antibody as well as it appears as a pentamer."
- **Analysis**: This statement is incorrect. IgA is not the most abundant antibody; IgG holds that title. Additionally, IgA typically exists as a dimer (two units) in secretions, not as a pentamer.

4. **Fourth Option**: "IgG is the most abundant antibody found in colostrum while IgG is found in case of hypersensitivity."
- **Analysis**: This statement is partially incorrect. While IgG is the most abundant antibody, it is not the one primarily found in colostrum; that role is filled by IgA. IgG is indeed involved in hypersensitivity reactions, but the statement is misleading regarding its presence in colostrum.

### Step 3: Conclusion
After analyzing all the options, the only correct statement is found in the second option: "Most abundant antibody is IgG and largest size is IgM."

### Final Answer
The correct answer is **Option 2**: "Most abundant antibody is IgG and largest size is IgM."

---