University:
York University
Course:
SC/BIOL 3120 | Immunobiology
Academic year:

2023
Views:

392

Pages:

3
Author:

Niklas

Antibody Effector Function 6 categories of Ab effector function Neutralization: Ab bind to Ag to stop them from binding to/entering the cell Agglutination: Ab bind multiple Ag, clumping Opsonization: Ab make viruses attractive for phagocytosis Complement activation: Ab bind and initiate classical complement ADCC: Ab-dependent cell-mediated cytotoxicity - cell-mediated apoptosis Degranulation: Ab binding induces degranulation Diagrams: Diagram 1: Shows the process of neutralization where Ab bind to Ag and prevent them from entering the cell. Diagram 2: Shows the process of agglutination where Ab bind multiple Ag and clump them together. Diagram 3: Shows the process of opsonization where Ab bind to a virus and make it attractive for phagocytosis. Diagram 4: Shows the process of complement activation where Ab bind to an Ag and initiate the classical complement pathway. Diagram 5: Shows the process of ADCC where Ab bind to a target cell and trigger NK cell-mediated apoptosis. Diagram 6: Shows the process of degranulation where Ab bind to a target cell and induce degranulation of immune cells. Innate vs Adaptive Immunity (Revisited) Independent of previous exposure Organ-specific Natural Killer (NK) cells: lymphoid origin but a part of the innate immune system Involved in cell-mediated immunity Discovered and named for their ability to kill tumor cells without prior exposure Important in defense against tumor/infected/stressed cells Cytotoxic activity is stimulated by IFN-γ, IFN-α, and IL-12 Peak effect 3 days post-infection Have direct cytotoxic activity but also secrete cytokines such as IFN-γ How do NK cells work? Missing self model: NK cells kill when class I MHC is not present Balanced signal model: integration of inhibitory and activating signals determines activation/inhibition NK cells express 2 types of receptors: Inhibitory: receive signals that inhibit NK activity Activating: receive signals that activate NK activity The tie-breaker goes to inhibitory cells, therefore cells expressing MHC class I will be tolerated