Which of the following is not an antibody type?

The correct answer, indicating the option that is not an antibody type, is the one labeled IgB. Antibodies, also known as immunoglobulins, are proteins produced by the immune system to help identify and neutralize foreign objects like bacteria and viruses. There are several classes of antibodies, known as immunoglobulin classes, which include IgA, IgE, and IgG. These classes play distinct roles in immune response:

• IgA is primarily found in mucosal areas such as the gut, respiratory tract, and urogenital tract, and it is involved in mucosal immunity.

• IgE is associated with allergic reactions and responses to parasites.

• IgG is the most abundant antibody in circulation and provides the majority of antibody-based immunity against invading pathogens.

The absence of an antibody type labeled IgB is what distinguishes it from the others, confirming that it is not recognized as a valid class of immunoglobulin in immunology. Therefore, the identification of IgB as not being an antibody type reinforces the understanding of immunoglobulin classification.