IgG subclasses

Immunoglobulins of the IgG class account for up to 80% of all immunoglobulins found in the blood. In the body, they are found in four subclasses 1 to 4. IgG are an active component of the acquired humoral response. IgG subclasses 1 through 3 together with IgM initiate the classical pathway of complement activation initiating the destruction of bacterial, virus-infected and tumor cells. IgG is produced by plasma cells. The IgG subclasses test is used to assess the humoral response and is mainly used in the diagnosis of primary immunodeficiencies.