Microbiology Practice Exam

What form of immunity does IgG provide?

1. Immediate response

2. Longer-lasting immunity

3. Primary response

4. Short-term immunity

The correct answer is: Longer-lasting immunity

IgG is a class of immunoglobulin critical for providing longer-lasting immunity, which is primarily due to its ability to remain in circulation for extended periods following an infection or vaccination. This persistence allows IgG to provide continued protection against the same pathogen upon re-exposure. The immune response involving IgG is typically associated with the secondary immune response, where the body has already encountered a specific antigen. Upon re-exposure, the immune system responds more rapidly and effectively, largely due to the presence of memory B cells that produce IgG. This response leads to a more robust and sustained immune protection, distinguishing it from other forms of immunity that are often temporary or rapid. In contrast, the immediate response, primary response, and short-term immunity are characteristics associated with other aspects of the immune system. The immediate response typically involves other immunoglobulin classes such as IgM, which are produced quickly during the first encounter with an antigen. The primary response refers to the initial response to an antigen, which is typically slower and not dominated by IgG. Meanwhile, short-term immunity often results from passive immunization (like maternal antibodies) or certain types of vaccines that provide temporary protection.