When does your body make antibodies? What activates the body to make antibodies or are they continually being produced?
Answers
Vertebrates inevitably die of infection if they are unable to make antibodies. Antibodies defend us against infection by binding to viruses and microbial toxins, thereby inactivating them (see Figure 24-2). The binding of antibodies to invading pathogens also recruits various types of white blood cells and a system of blood proteins, collectively called complement (discussed in Chapter 25). The white blood cells and activated complement components work together to attack the invaders.
Synthesized exclusively by B cells, antibodies are produced in billions of forms, each with a different amino acid sequence and a different antigen-binding site. Collectively called immunoglobulins (abbreviated as Ig), they are among the most abundant protein components in the blood, constituting about 20% of the total protein in plasma by weight. Mammals make five classes of antibodies, each of which mediates a characteristic biological response following antigen binding. In this section, we discuss the structure and function of antibodies and how they interact with antigen