Adaptive Immunity Concepts Quiz

Lecture 19 – Adaptive Immunity: Key Concepts

• The alternative pathway of complement activation leads to three outcomes: Complement C3b coating the target, C3a diffusing as a chemoattractant, and C5a binding to the target forming the membrane attack complex.
• Natural killer cells recognize cells without Major Histocompatibility Complex I (MHC1) proteins, inducing apoptosis through granzyme and perforin release.
• Interferons, produced by virally infected cells, prevent viral replication by stimulating antiviral protein production in uninfected cells.
• Adaptive immunity involves B and T lymphocytes, with B cells producing antibodies and T cells defending against intracellular pathogens.
• Lymphocyte receptors interact with individual antigens, with T cells displaying antigen-specific T cell receptors and B cells displaying membrane-bound immunoglobulins.
• Memory cells are formed upon first antigen exposure, leading to rapid and strong responses upon subsequent exposures.
• The primary immune response involves B and T cell activation, proliferation, and differentiation upon first antigen exposure.
• Continuous exposure to an antigen does not result in a secondary immune response, requiring a refractory period for memory cell formation.
• Secondary immune responses, resulting in a stronger and faster reaction, are activated upon subsequent exposure to the same antigen.
• Tolerance is the acquired ability to discriminate between self and foreign antigens, with failure leading to autoimmunity.
• T cell selection involves positive and negative selection in the thymus, with clonal deletions eliminating most T cells that enter.
• B cell selection involves positive selection upon encountering an antigen, leading to proliferation and differentiation, and negative selection in the bone marrow to delete self-reactive B cells.