Which immunoglobulin is the most common type found in the body?

The most common immunoglobulin found in the body is IgG. This class of antibody plays a crucial role in the immune response by identifying and neutralizing pathogens like bacteria and viruses. IgG is the only antibody that can cross the placenta, providing passive immunity to the fetus during pregnancy. It constitutes a significant portion of the antibodies in serum, usually around 75-80%, thereby making it the predominant antibody type in circulation. Its constant region can bind to a receptor on phagocytic cells, enhancing the immune response through opsonization and facilitating the clearance of pathogens. This extensive distribution and multifunctional capabilities make IgG essential for long-term immunity.

In contrast, other immunoglobulin types, while important in specific contexts, do not match IgG's overall prevalence and versatility in the body's immune landscape.