Immunoglobin G
Synopsis of immunoglobin G
Immunoglobulin G (IgG) is the most abundant class of antibodies in the human body, comprising approximately 75–80% of the total immunoglobulin pool in the blood and extracellular fluid. Produced by plasma B cells, IgG plays a central role in the adaptive immune response, helping to identify and neutralize pathogens such as bacteria, viruses, and toxins. Each IgG molecule has a Y-shaped structure that binds specifically to antigens, tagging them for destruction by other immune cells.
IgG is critical for long-term immunity and immunological memory, and it is the only class of antibody that can cross the placenta, providing passive immunity to newborns. There are four subclasses of IgG in humans—IgG1, IgG2, IgG3, and IgG4—each with slightly different functions and antigen targets.
IgG mediates its immune effects through various mechanisms:
- Neutralizing pathogens directly
- Activating the complement system (a group of proteins that aid in clearing microbes)
- Opsonization (marking invaders for destruction by phagocytes)
- Antibody-dependent cellular cytotoxicity (ADCC)
Clinically, IgG levels are measured to assess immune function, infection history, autoimmune activity, or to monitor responses to vaccines. Elevated or deficient levels can signal underlying issues such as chronic infections, immune deficiencies (like Common Variable Immune Deficiency), or autoimmune diseases (e.g., lupus, rheumatoid arthritis).
Historical and Clinical Use
IgG was first identified as a distinct antibody class in the 20th century, during early immunological research that classified different serum proteins. Its central role in acquired immunity has made it a major focus in vaccine development, diagnostics, and immunotherapy.
In modern medicine, intravenous or subcutaneous immunoglobulin therapy (IVIG/SCIG)—which consists mostly of purified IgG—is used to treat a variety of conditions, including:
- Primary immunodeficiencies
- Autoimmune diseases (by modulating overactive immune responses)
- Chronic inflammatory conditions (like Guillain-Barré syndrome or myasthenia gravis)
Additionally, IgG-based food sensitivity testing has emerged in functional medicine, where IgG antibodies are measured against certain foods to identify potential delayed hypersensitivity reactions, though this practice is controversial and not widely accepted in mainstream immunology.
Today, immunoglobulin G remains a cornerstone of immune defense and immune-based therapies, bridging diagnostics, treatment, and prevention across a broad range of health conditions.
Immunoglobin G is used for these health conditions
Autoimmune Disorders (Scientific)
Colitis (Scientific)
Infection (Scientific)
Infection (bacterial) (Scientific)
Infection (viral) (Scientific)
Inflammation (Scientific)
Leaky Gut Syndrome (Scientific)
Lupus (Scientific)
Pneumonia (Scientific)
Rashes and Hives (Scientific)
Sinus Infection (Scientific)
Staph Infections (Scientific)
immunoglobin G is used to support these body systems
Gastrointestinal Tract (Scientific)
Immune System (Scientific)
Intestinal System (Scientific)
Peyer’s patches (Scientific)
Small Intestines (Scientific)
