During the secondary immune response, which antibody class is predominantly formed?

In the secondary immune response, the predominant antibody class formed is IgG. This is a critical aspect of the immune system's memory function. When the body encounters a pathogen for the first time, it typically produces IgM antibodies initially. IgM is effective in the early stages of an immune response but is not as effective in neutralizing toxins or viruses as IgG.

Upon re-exposure to the same pathogen, the immune system has "memory" cells that recognize the specific antigens of that pathogen. This leads to a more rapid and robust response compared to the primary immune response. During this secondary response, B cells differentiate primarily into plasma cells that produce IgG antibodies. IgG is more effective in opsonization, neutralization, and activation of the complement system, making it a crucial antibody in conferring long-term immunity.

The other antibody classes, such as IgE and IgA, serve specific roles in immune defense. IgE is involved in allergic reactions and defense against parasitic infections, while IgA is predominantly found in mucosal areas, such as the gut and respiratory tract. However, in terms of a robust and long-lasting response following re-exposure, IgG is the dominant and most important antibody produced.