In the immune response, which antibody class is produced first in the secondary immune response?

In the secondary immune response, the antibody class that is produced first is IgG. This response occurs when the immune system encounters a previously recognized pathogen. Upon re-exposure to the same antigen, memory B cells that were generated during the primary immune response become activated more quickly than during the initial encounter.

During the primary immune response, IgM is typically the first antibody produced, but the secondary response is characterized by a faster and more robust production of IgG. This rapid increase in IgG levels provides enhanced protection against the pathogen due to its higher affinity for the antigen and its ability to effectively neutralize and opsonize pathogens, as well as activate complement more efficiently.

IgE and IgA are associated with different immune functions; IgE is primarily involved in allergic responses and defense against parasitic infections, while IgA plays a crucial role in mucosal immunity. However, the first class of antibody produced in response to re-exposure to a familiar pathogen is IgG, making it a key player in the secondary immune response.