International Board of Certified Lactation Consultant (IBCLC) Practice Exam

What is the major immunoglobulin in human milk that prevents pathogens from attaching to the mucosal surfaces?

1. IgM

2. IgG

3. Secretory IgA

4. IgE

The correct answer is: Secretory IgA

The major immunoglobulin in human milk that plays a crucial role in protecting infants from infections is secretory IgA. Secretory IgA is specifically designed to prevent pathogens, such as viruses and bacteria, from adhering to mucosal surfaces in the gastrointestinal tract and respiratory system. By blocking these pathogens from attaching, secretory IgA significantly reduces the risk of infection and helps to establish a strong immunity in the breastfeeding infant. Secretory IgA is unique because it can survive the harsh environment of the gastrointestinal tract, making it particularly effective for infant immunological defense. Unlike other immunoglobulins, secretory IgA is also resistant to degradation by proteolytic enzymes found in the gut, which further enhances its protective capabilities. The other types of immunoglobulins listed, such as IgM, IgG, and IgE, have different roles in the immune response. For instance, IgM is typically the first antibody produced in response to an infection, while IgG is important for long-term immunity and can cross the placenta, providing some protection to the fetus. IgE is primarily involved in allergic reactions and responses to parasitic infections. However, none of these immunoglobulins are as critical as secretory IgA when it comes to