immunoglobulin complex

Definition

Target type: cellularcomponent

A protein complex that in its canonical form is composed of two identical immunoglobulin heavy chains and two identical immunoglobulin light chains, held together by disulfide bonds and sometimes complexed with additional proteins. An immunoglobulin complex may be embedded in the plasma membrane or present in the extracellular space, in mucosal areas or other tissues, or circulating in the blood or lymph. [GOC:add, GOC:jl, ISBN:0781765196]

Immunoglobulin complexes are intricate molecular assemblies composed of antibodies (immunoglobulins) bound to their cognate antigens. These complexes play a crucial role in the adaptive immune response, mediating the recognition and neutralization of pathogens, toxins, and other harmful substances. The cellular component of immunoglobulin complexes encompasses a diverse array of cellular structures and compartments involved in their formation, trafficking, and signaling.

The synthesis of immunoglobulin complexes begins within B lymphocytes, where antibody genes are transcribed, translated, and assembled into functional immunoglobulins. Following their synthesis, immunoglobulins are transported to the endoplasmic reticulum (ER), a cellular organelle responsible for protein folding and modification. Within the ER, immunoglobulin chains undergo post-translational modifications, including glycosylation and disulfide bond formation, which are essential for proper antibody structure and function.

Subsequently, immunoglobulin complexes are transported from the ER to the Golgi apparatus, another cellular organelle involved in protein sorting and packaging. In the Golgi, immunoglobulins are further processed, sorted, and packaged into vesicles. These vesicles then bud off from the Golgi and travel to the plasma membrane, where they are released into the extracellular space.

Once secreted, immunoglobulins can bind to their specific antigens, forming immunoglobulin complexes. These complexes can engage with various cellular components, depending on the nature of the antigen and the context of the immune response.

For example, immunoglobulin complexes can bind to cell surface receptors on B lymphocytes, triggering B cell activation and antibody production. They can also bind to complement proteins, initiating a cascade of events that leads to the formation of the membrane attack complex (MAC), which can lyse target cells. Additionally, immunoglobulin complexes can bind to Fc receptors on various immune cells, such as macrophages, neutrophils, and natural killer (NK) cells, triggering phagocytosis, antibody-dependent cellular cytotoxicity (ADCC), and other effector functions.

In conclusion, the cellular component of immunoglobulin complexes encompasses a complex network of organelles, proteins, and signaling pathways involved in their formation, trafficking, and interaction with other cellular components. These interactions are essential for the effective functioning of the adaptive immune response and the protection of the host against pathogens and other harmful substances.'
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Proteins (1)

Compounds (1)