AAMC FL Practice Exam

What function do B cells serve in the immune system?

1. They attack infected cells directly

2. They produce antibodies to fight pathogens

3. They regulate blood cell production

4. They help in the formation of the thymus

The correct answer is: They produce antibodies to fight pathogens

B cells play a crucial role in the immune system primarily through their ability to produce antibodies. When B cells encounter a pathogen, they can differentiate into plasma cells, which are specialized cells that secrete large volumes of antibodies. These antibodies are proteins that specifically bind to antigens, which are foreign molecules present on pathogens. The binding of antibodies to their specific antigens marks these pathogens for destruction or neutralization by other immune cells and helps prevent the spread of infection. The ability of B cells to remember specific pathogens also contributes to long-term immunity. After an infection, some B cells become memory cells that provide a faster and more effective response if the same pathogen is encountered again in the future. This process highlights the specific function of B cells within the adaptive immune response, primarily focusing on antibody production as their central role.