Question

Which class of immunoglobulin has the highest concentration in the human body?

• A. IgA
• B. IgG
• C. IgM
• D. IgE

Hint:

{IgG} constitutes about {70–75% of total serum immunoglobulins} and can cross the placenta to provide passive immunity to the fetus.

Answer 1

The Correct Option is B

Concept: Immunoglobulins (antibodies) are proteins produced by plasma cells that play a crucial role in the immune response. There are five major classes of immunoglobulins: IgG, IgA, IgM, IgD, and IgE. Among these, IgG is the most abundant immunoglobulin in human serum and body fluids. It plays an important role in long-term immunity and protection against infections.
Step 1: Identify the immunoglobulin with the highest concentration in serum.

• IgA – Mainly present in mucosal secretions.
• IgG – Most abundant immunoglobulin in serum.
• IgM – First antibody produced during primary immune response.
• IgE – Involved in allergic reactions and parasitic infections.

Thus, the immunoglobulin with the highest concentration in the human body is IgG.