Ig Antibodies subtypes | Full Lecture | Immunology | Basic Science Series

Ig Antibodies subtypes | Immunology | Basic Science Series

1. The structure of Immunoglobulin G (IgG) antibodies showcases a molecular makeup, typically around 150 kilodaltons, arranged in a tetrameric form.

2. Each IgG molecule is composed of both heavy and light protein chains that includes two heavy (H) chains and two light (L) chains, each pair identical to its counterpart.

3. The heavy chains, known as gamma (γ) chains, each weigh approximately 50 kilodaltons and are matched with light chains weighing around 25 kilodaltons.

4. These chains are interconnected through disulfide bonds, forming a structure with two symmetrical halves that collectively resemble a Y shape.

5. The structure of the heavy chain includes several distinct regions: CH1, CH2, CH3, a hinge region for flexibility, and the VH region. IgG subclasses

6. Humans possess four subclasses of Immunoglobulin G (IgG), labeled IgG1, IgG2, IgG3, and IgG4, arranged according to their prevalence in blood serum, with IgG1 being the most commonly found.

7. IgG antibody subclasses are distinguished by various factors:

8. Variations in the hinge region's length

9. The location of disulfide bonds between chains

10. Overall molecular weights.

11. Capabilities to trigger the complement system

12. IgG1: This subclass represents 60-65% of the total IgG and is chiefly responsible for immune reactions to proteins and polypeptides.

13. IgG2: Accounting for 20-25% of IgG, IgG2 is primarily responsive to antigens found on carbohydrates and polysaccharides.

14. Deficiencies in IgG2 often leads to repeated respiratory infections in young children.

15. IgG3: Making up about 5-10% of the total IgG, IgG3 is significant in the body's defense against protein or polypeptide antigens, similar to IgG1 but less prevalent.

16. IgG4: The least abundant, constituting less than 4% of IgG, IgG4 does not typically react with polysaccharide antigens. • Infection Control: IgG circulates in blood and extracellular fluid to combat body tissue infections. • Neonatal Protection: The only antibody crossing the placenta, IgG safeguards newborns early on. • Opsonization and Phagocytosis: IgG marks pathogens for destruction and enhances phagocyte binding for immune response. • Longevity and Immunization: Essential for long-term passive immunity, IgG indicates past infections or vaccinations, crucial in research and diagnostics. WhatsApp group: https://chat.whatsapp.com/HTXQC1Ax2qfKYa3MrZiMeD Twitter: https://twitter.com/basic_series Facebook Group: https://www.facebook.com/groups/742235929758671 LinkedIn: https://www.linkedin.com/in/basic-science-series-a54439208/ Instagram: https://www.instagram.com/basic_science_series/ Support my work at https://www.patreon.com/user?u=37177596

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