Part 3 Flashcards
What is humoral immunity?
Antibodies are produced that target extracellular antigens.
What occurs during the primary response in adaptive defenses?
Initial encounter with antigen.
What are B lymphocytes?
Specific cells that have receptors for antigens.
What happens to B lymphocytes with noncomplementary receptors?
They remain inactive.
What is the result of B cell activation?
Proliferation to form a clone.
What are plasma cells?
Effector B cells that secrete antibodies.
What is a memory B cell?
A cell primed to respond to the same antigen.
What does the antibody titer indicate?
Antibody concentration in plasma.
True or False: The primary immune response to antigen A is faster than the secondary response.
False.
What characterizes the secondary immune response to the same antigen?
It is faster, more prolonged, and more effective.
What occurs upon re-exposure to the same antigen?
Faster, more prolonged, more effective antibody response.
What are the two types of humoral immunity?
- Active
- Passive
How is naturally acquired active immunity obtained?
Infection; contact with pathogen.
What is artificially acquired active immunity?
Vaccine; dead or attenuated pathogens.
How is naturally acquired passive immunity conferred?
Antibodies passed from mother to fetus via placenta or to infant in her milk.
What is artificially acquired passive immunity?
Injection of exogenous antibodies (gamma globulin).
What are antibodies?
Proteins secreted by B (plasma) cells in response to an antigen.
What is the structure of antibodies?
Four polypeptide chains linked by disulfide bonds.
What are the two regions of each polypeptide chain in antibodies?
- Variable (V) region
- Constant (C) region
What are the functions of antibodies?
Inactivate and tag antigens; do NOT directly destroy them.
What defensive mechanisms do antibodies use?
- Precipitation
- Complement fixation and activation
- Agglutination
- Neutralization
What is the role of the antigen-antibody complex?
Antibody inactivates the antigen.
What is the role of complement in antibody function?
Enhances phagocytosis, inflammation, and leads to cell lysis.
What is agglutination in the context of antibodies?
Clumping of cell-bound antigens.
