Which antibody is produced first in response to an antigen during an initial immune response?

Which antibody is produced first in response to an antigen during an initial immune response?

• A. IgA
• B. IgG
• C. IgM
• D. IgE

Answer: (C)

The first antibody produced in response to an antigen during an initial immune response is IgM. When the body encounters a new pathogen, it triggers the activation of B cells that differentiate into plasma cells. These plasma cells initially produce IgM antibodies, which are effective in identifying and neutralizing pathogens.

IgM is particularly well-suited for the early stages of the immune response because it is primarily responsible for the agglutination of pathogens and the activation of the complement system, which aids in the destruction of invading microorganisms. This early production of IgM provides a rapid response to infections while the immune system is gearing up to produce other types of antibodies, such as IgG, which offer more specialized and long-lasting immunity.

Therefore, during the early phase of an immune response, the prevalence of IgM is critical in controlling the immediate threat posed by pathogens.