International Board of Certified Lactation Consultant (IBCLC) Practice Exam

Which immunoglobulin plays a crucial role in the immune function of breast milk?

1. IgE

2. IgM

3. IgA

4. IgG

The correct answer is: IgA

Immunoglobulin A (IgA) is the primary immunoglobulin found in breast milk, particularly in its secretory form, known as secretory IgA (sIgA). This specific form of IgA is crucial for mucosal immunity, as it protects the infant’s gastrointestinal tract from infections by binding to pathogens and preventing their adherence to mucosal surfaces. By doing this, sIgA helps neutralize harmful bacteria and viruses, which is especially important during the early stages of life when the infant's immune system is still developing. In addition to offering protection against pathogens, IgA provides passive immunity, meaning that it helps protect the infant during the early months of life before their own immune system has fully matured. Breast milk, through the presence of IgA and other immune factors, creates a vital barrier that supports the infant’s immune health and contributes to overall well-being. While IgE, IgM, and IgG are other types of immunoglobulins that play important roles in the immune response, they are not the principal immunoglobulin involved in the immune function of breast milk. IgE is primarily associated with allergic reactions, IgM is typically the first antibody produced in response to an infection, and IgG is the most