Question

Which antibody class is most abundant in human serum?

• A. IgA
• B. IgD
• C. IgE
• D. IgG

Hint:

Remember the order of abundance in serum using the acronym: {GAMED} (IgG > IgA > IgM > IgD > IgE).

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
In humans, there are five classes of immunoglobulins (antibodies): IgA, IgD, IgE, IgG, and IgM. They differ in their biological properties, locations, and concentrations.
Step 2: Detailed Explanation:
IgG is the most prevalent antibody class in the blood and tissue fluids, making up about \(75-80%\) of the total serum antibodies.
It is highly significant because it can cross the placenta to provide passive immunity to the fetus.
- IgA (Option A) is the most abundant antibody in secretions (breast milk, saliva, mucus).
- IgM is the first antibody produced during an initial immune response.
- IgE (Option C) is involved in allergic reactions.
Step 3: Final Answer:
IgG is the antibody class that exists in the highest concentration in human serum.