IgAIgG

IgAIgG is a term that appears in some scientific discussions to refer to interactions, constructs, or concepts involving both immunoglobulin A (IgA) and immunoglobulin G (IgG). It is not a standard or widely adopted term in immunology, and there is no universally accepted definition.

IgA and IgG are distinct antibody isotypes with different roles. IgA is the main antibody class at mucosal surfaces and in secretions, providing defense at entry points of the body. IgG circulates in the bloodstream and tissues, mediating neutralization, opsonization, antibody-dependent cellular cytotoxicity, and complement activation via its Fc region and Fc receptors.

In practice, IgAIgG may denote one of several concepts. It could refer to a co-dominant immune response involving both IgA and IgG in a given reaction; it could describe an engineered antibody construct that combines features of both isotypes, such as a chimeric or bispecific molecule designed to harness mucosal binding from IgA with systemic effector functions from IgG; or it could be a shorthand for cross-isotype immune complexes formed by IgA and IgG.

Applications and challenges for IgAIgG concepts include potential therapeutic approaches aiming to improve targeting across mucosal and systemic compartments, offset by concerns about stability, manufacturability, immunogenicity, and regulatory considerations. In diagnostics and research, precise definitions are essential to prevent misinterpretation of results labeled as IgAIgG.

Because the term lacks standardization, readers should rely on context-specific definitions in the sources that use it. Related topics include Immunoglobulin A, Immunoglobulin G, Fc receptors, and bispecific antibodies.