TGG3 Antibody

Introduction to IgG3 Antibody

Immunoglobulin G3 (IgG3) is a subclass of IgG antibodies that plays a crucial role in the immune system's response to infections and other threats . IgG antibodies are the most abundant type of antibody found in blood and extracellular fluid, where they work to control infection of body tissues . They achieve this by binding to pathogens like viruses, bacteria, and fungi, thereby protecting the body from infection through mechanisms such as immobilization, agglutination, opsonization (coating of pathogen surfaces), complement system activation, and toxin neutralization .

IgG3 in Cancer Research

• Targeting Tumor Antigens IgG3 monoclonal antibodies can be developed to target specific carbohydrate antigens expressed on tumor cells, such as unbranched polylactosamine structures .

• Immunohistochemical Staining These antibodies can be used in immunohistochemical staining to study the distribution of antigens in tissue sections, aiding in the diagnosis and understanding of cancer .

• Prevalence in Tumor Tissues Studies have shown a high incidence of positive staining in colon cancer and hepatocellular carcinoma, indicating the potential of IgG3 antibodies in cancer therapy .

IgG3 in Immunotherapy

• T-Cell Activation and Anti-tumor Activity Trispecific antibodies that incorporate a CD3/CD28 co-engagement mechanism can induce potent tumor-directed T-cell activation and anti-tumor activity, showcasing their potential in T-cell-based immunotherapies .

• Enhanced T-Cell Immunity These trispecific antibodies augment T-cell activation, promote memory T-cell differentiation, and induce faster tumor cell lysis compared to bispecific antibodies .

• Modulation of T-Cell Signals IgG3 antibodies can modulate CD3/TCR complex-derived signals and upregulate antiapoptotic factors, influencing the survival and effectiveness of T-cells in immunotherapy .

IgG3 in Viral Neutralization

• Broad Neutralization of Viral Variants IgG3 antibodies have demonstrated increased neutralization of antigenically drifted variants of influenza virus and SARS-CoV-2, highlighting their importance in combating viral infections .

• Impact of IgG Subclass on Antibody Breadth The IgG subclass is a determinant of antibody breadth, with IgG3 providing increased neutralization of antigenically drifted virus variants .

• Role of Hinge Region The extended hinge length of IgG3 contributes to enhanced neutralization of HIV-1, showcasing the structural advantages of this subclass in viral defense .

IgG3 in Autoimmune Diseases

• Reduction of Autoantibody Levels IgG1 antibodies, such as nipocalimab, can significantly reduce autoantibody levels in autoimmune diseases like generalized myasthenia gravis (gMG) .

• Clinical Improvement in gMG Nipocalimab has demonstrated clinically meaningful improvement in patients with gMG by reducing IgG, including pathogenic IgG, which underlies autoantibody diseases .

• Phase 3 clinical trial data indicates that Nipocalimab reduces autoantibody levels by up to 75% over a 24 week period .

IgG3 Production and Function

• B Cell Production IgG molecules are produced and released by plasma B cells as part of the humoral immune response .

• Mechanisms of Pathogen Elimination IgG antibodies protect against infection through various mechanisms, including agglutination, opsonization, complement activation, and toxin neutralization .

• Antibody-Dependent Cell-Mediated Cytotoxicity (ADCC) IgG plays a crucial role in ADCC, where it binds to TRIM21 to direct virions to the proteasome for intracellular antibody-mediated proteolysis .

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