What are the five classes of immunoglobulins?

What are the five classes of immunoglobulins?

• A. IgG, IgA, IgD, IgE, IgM.
• B. IgG, IgA, IgM, IgD, IgE.
• C. IgG, IgA, IgD, IgE, IgM.
• D. IgD, IgE, IgG, IgA, IgM.

Answer: (C)

Five classes of antibodies exist: IgG, IgA, IgM, IgD, and IgE. They are defined by the constant region of their heavy chains (gamma for IgG, alpha for IgA, mu for IgM, delta for IgD, epsilon for IgE) and each class has distinct roles in immunity. IgG is the most abundant in serum and supports opsonization and neutralization; IgA protects mucosal surfaces and is abundant in secretions; IgM is the first antibody produced in a primary response and often forms pentamers; IgD mainly serves as a B cell receptor; IgE is involved in allergic responses and defense against parasites. In this question, recognizing the five classes is the key; any option that lists all five earns credit, since the exact order of presentation is not essential to the concept.

Five classes of antibodies exist: IgG, IgA, IgM, IgD, and IgE. They are defined by the constant region of their heavy chains (gamma for IgG, alpha for IgA, mu for IgM, delta for IgD, epsilon for IgE) and each class has distinct roles in immunity. IgG is the most abundant in serum and supports opsonization and neutralization; IgA protects mucosal surfaces and is abundant in secretions; IgM is the first antibody produced in a primary response and often forms pentamers; IgD mainly serves as a B cell receptor; IgE is involved in allergic responses and defense against parasites. In this question, recognizing the five classes is the key; any option that lists all five earns credit, since the exact order of presentation is not essential to the concept.