Question

The most abundant class of immunoglobulins in serum is ________.

• A. ( IgM )
• B. ( IgA )
• C. ( IgD )
• D. ( IgG )

Hint:

Understanding the distinct functions of different immunoglobulin classes is key in fields like immunology and medical diagnostics, where antibody presence and type can indicate the stage or type of an ongoing immune response.

Answer 1

The Correct Option is D

Immunoglobulins (Ig), also known as antibodies, play a crucial role in the immune system by identifying and neutralizing foreign objects like bacteria and viruses. Each class of immunoglobulin has specific roles and characteristics. 
Overview of Immunoglobulin Classes: 
(A) IgM: Often the first antibody produced in response to an infection, prominent in early immune responses. 
(B) IgA: Mainly found in mucous membranes lining the respiratory and gastrointestinal tracts, as well as in secretions like saliva and tears. 
(C) IgD: Functions mainly as a receptor on B cells that have not been exposed to antigens. 
(D) IgG: Correct. IgG is the most abundant type of antibody in the blood and extracellular fluid, making up about 75% to 80% of all antibodies in the body. It is critical for fighting bacterial and viral infections and is the only antibody capable of crossing the placenta to provide passive immunity to the fetus. Conclusion:
Explanation: IgG antibodies are not only prevalent but also pivotal in their capacity to mediate immune responses, including secondary immune responses and memory immunological responses, making them essential for long-term immunity.