Immunity and Antibody Quiz

Immunity Types

• Artificially Acquired Active Immunity: Gained through vaccination.
• Artificially Acquired Passive Immunity: Involves transferring antibodies via injection.
• Naturally Acquired Active Immunity: Developed after recovering from an infection, such as mumps.
• Naturally Acquired Passive Immunity: Newborns receive antibodies through the placenta.

Antibody Interactions

• Epitope: Specific antigen regions that interact with antibodies.
• Neutralization: When an antibody binds to a toxin, it neutralizes its harmful effects.
• ADCC (Antibody-Dependent Cellular Cytotoxicity): Mediated by immune cells recognizing antibody-coated targets.

T Cells and Antigen Recognition

• CD4+ T Cells Activation: Triggered by the interaction of CD4+ with MHC II molecules.
• TH Cell: Recognizes antigens presented on host cells with MHC II.

Structure and Function of Antibodies

• Specificity of Antibodies: Determined by the variable portions of heavy (H) and light (L) chains.
• Types of Antibodies:
  • IgG: Most abundant in serum and involved in complement fixation.
  • IgM: Large antibodies that agglutinate antigens; also fixes complement.
  • IgA: Found in secretions like mucus and saliva.
  • IgD: Primarily found on the surface of B cells; not secreted.
  • IgE: Binds to large parasites and mediates allergic reactions.

B Cells and Cellular Immunity

• B Cells Characteristics:
  • Originate in the bone marrow and possess antibodies on their surfaces.
  • Responsible for memory response and antibody production.
• T Cells Characteristics:
  • Originate in bone marrow, processed in the thymus, and can inhibit immune responses.

Other Key Points

• Antigen-Antibody Reactions: Outcomes include opsonization, activation of complement, and agglutination; clonal deletion is NOT an outcome.
• Antigen Presentation: Natural killer cells do not act as antigen-presenting cells (APCs); APCs include dendritic cells, macrophages, and mature B cells.
• Plasma Cells Activation: Triggered by antigen exposure.