IgA: Structure, Properties and Functions (FL-Immuno/39)

TL;DR

Immunoglobulin A (IgA) is a predominant antibody in mucous secretions, and it has two subclasses: IgA1 and IgA2. IgA can exist in two forms: secreted IgA and secretory IgA.

Transcript

in this video lecture we will study the structure properties and function of immunoglobulin a besides this we will also understand the difference between secreted and secretory immunoglobulins immunoglobulin a is found in blood but it is predominant in the secretions of the body for example in the mucous mother's milk tears and saliva structurally ... Read More

Key Insights

• 🔬 Immunoglobulin A (IgA) is found predominantly in mucous secretions, protecting mucosal surfaces.
• 🔬 IgA has two subclasses, IgA1 and IgA2, which differ in the hinge region.
• 🔬 IgA can exist as secreted IgA in the bloodstream and secretory IgA at mucosal surfaces.
• ❓ Secretory IgA undergoes modification, including the addition of a secretory component for protection and transportation.
• 🔬 IgA is the most abundant immunoglobulin in the human body when considering production at mucosal surfaces.
• 🔬 IgA in colostrum provides passive immunity to infants, protecting them from gastrointestinal infections.
• 🚫 IgA prevents pathogens from adhering to mucosal surfaces, blocking their entry into the bloodstream.

Questions & Answers

Q: What is the difference between secreted IgA and secretory IgA?

Secreted IgA circulates in blood and can be a monomer, dimer, or trimer. Secretory IgA is predominant in mucosal surfaces and undergoes modification, including the addition of a secretory component, which helps with transportation and protection from enzymes in secretions.

Q: What is the role of IgA in colostrum?

IgA is the major antibody found in colostrum, providing passive immunity to infants. It protects them from gastrointestinal infections and neutralizes toxins and pathogens.

Q: How does IgA prevent pathogens from entering the bloodstream?

IgA blocks pathogens from adhering to mucosal surfaces, preventing their entry into the bloodstream.

Q: What is the function of IgA in antibody-dependent cell-mediated cytotoxicity?

IgA triggers degranulation of granulocytes and plays a role in antibody-dependent cell-mediated cytotoxicity by binding to specific Fc receptors on killer cells.

Key Insights:

• Immunoglobulin A (IgA) is found predominantly in mucous secretions, protecting mucosal surfaces.
• IgA has two subclasses, IgA1 and IgA2, which differ in the hinge region.
• IgA can exist as secreted IgA in the bloodstream and secretory IgA at mucosal surfaces.
• Secretory IgA undergoes modification, including the addition of a secretory component for protection and transportation.
• IgA is the most abundant immunoglobulin in the human body when considering production at mucosal surfaces.
• IgA in colostrum provides passive immunity to infants, protecting them from gastrointestinal infections.
• IgA prevents pathogens from adhering to mucosal surfaces, blocking their entry into the bloodstream.
• IgA triggers degranulation of granulocytes and plays a role in antibody-dependent cell-mediated cytotoxicity.

Summary & Key Takeaways

• Immunoglobulin A (IgA) is found predominantly in mucous secretions, such as mother's milk, tears, and saliva.

• IgA consists of two light chains and two alpha-heavy chains, with two subclasses: IgA1 and IgA2.

• IgA can exist as secreted IgA in blood and secretory IgA at mucosal surfaces.