Focus on antibodies in relation to B lymphocytes and their role in the immune response.
Antibodies help the body recover from infections by binding to antigens.
Antibodies vs. Antibiotics
Antibodies: Proteins produced by the immune system to neutralize pathogens.
Antibiotics: Drugs used to kill bacteria.
Structure of Antibodies
Antibodies are quinary globular glycoproteins.
Protein: Made of amino acids linked by peptide bonds.
Globular: Spherical and water-soluble.
Quinary Structure: Composed of more than one polypeptide chain.
Glycoproteins: Attached to sugars.
Composed of four polypeptide chains:
2 Heavy (long) chains
2 Light (short) chains
Chains are linked by disulfide bridges (strong covalent bonds).
Antigen Binding Sites: Two per antibody, allowing binding to two antigens.
Constant vs. Variable Regions:
Constant Region: Same amino acid sequence across antibodies.
Variable Region: Different amino acid sequences to bind specific antigens.
Function of Antibodies
Prevent Infection: Bind to virus antigens, stopping them from entering cells and replicating.
Facilitate Phagocytosis:
Bind to bacterial flagella to slow movement, aiding phagocyte capture.
Neutralize Toxins: Bind to bacterial toxins to prevent cell damage (e.g., neutralizing cholera toxin).
Clump Pathogens: Use hinge region for flexibility, bind multiple pathogens to prevent their free movement.
Opsonization: Enhance phagocytosis by binding to phagocyte receptors with heavy chains.
Conclusion
Antibodies play a crucial role in defending against infections by neutralizing pathogens, facilitating phagocytosis, and preventing pathogen spread in the body. They enable recovery from infections by mitigating pathogen damage.