Question

Which is the first antibody produced in the primary immune response?

• A. IgM
• B. IgA
• C. IgG
• D. IgD

Hint:

IgM is the first line of defense against pathogens and plays a key role in activating the immune system during the initial stages of infection.

Answer 1

The Correct Option is A

IgM is the first antibody produced during the primary immune response. It is produced by B cells upon their first exposure to a specific antigen. IgM is a large pentameric antibody that is highly effective at neutralizing pathogens and activating the complement system. It is typically the first type of antibody to appear in the blood following an infection or vaccination.

(1) IgM Production:
- During the primary immune response, IgM is produced in large quantities, and its levels decrease as IgG production increases during the later stages of the immune response.

(2) Why Other Options Are Incorrect:
- IgA (Option 2) is important for mucosal immunity but is not the first antibody produced in a primary immune response.
- IgG (Option 3) is produced later in the immune response, after IgM, and is more abundant in secondary immune responses.
- IgD (Option 4) is mainly found on the surface of B cells and is involved in initiating the immune response, but it is not the first antibody produced during the immune response.

Conclusion: The first antibody produced in the primary immune response is IgM, which plays a crucial role in the early stages of the immune system's defense against pathogens.