Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025
Definition
An isotype refers to the different classes of antibodies (IgA, IgD, IgE, IgG, and IgM) found in all individuals of a species. These classes are determined by the constant region of the heavy chain in the antibody structure.
5 Must Know Facts For Your Next Test
Isotypes vary in their heavy chain constant regions which define their functional properties.
Human antibodies have five main isotypes: IgA, IgD, IgE, IgG, and IgM.
Each isotype has a distinct role in immune responses; for instance, IgG is crucial for opsonization.
Isotypes can be involved in different immune functions such as neutralization of pathogens or activation of complement systems.
The distribution and function of antibody isotypes can affect how effectively an immune response combats pathogens.