571. Lack of reaction to our own human leukocyte antigens (HLAs) is known as?
A. autoimmunity
B. complement system
C. clonal selection
D. tolerance

572. Which of the following components of the vertebrate immune response occurs first upon invasion by a virus or bacterium?
A. Activation of killer T lymphocytes
B. Activation of B lymphocytes
C. The inflammatory response
D. Mobilization of complement proteins

573. Which of the following white blood cells act as scavengers when they engulf and digest pathogens?
A. Macrophages
B. T cells
C. B cells
D. Lymphocytes

574. A cell which defends against body cells in which viruses are reproducing is
A. Exotoxin
B. Cytotoxic T cell
C. Endotoxin
D. Suppressor T cell

575. Which of the following is most likely to produce anaphylaxis in a susceptible individual?
A. Pollen
B. Mold
C. Dust
D. Bee sting

576. What type of B cell remains dormant in the body, but can respond rapidly if the same antigen appears again?
A. T cells
B. Memory cells
C. Plasma cells
D. Macrophages

577. The maturation of T cells and the production of particular T cell receptors occurs in the
A. thyroid gland
B. thymus gland
C. testes
D. all of these

578. Which of the following provide specific defense against viruses and bacteria?
A. T cells
B. B cells
C. Complement
D. inflammation

579. Which of these is a type of specific defense against pathogens?
A. Lymphocytes
B. Macrophages
C. Phagocytes
D. Leukocytes

580. In animals, blood clots serve the function of
A. consuming invading organisms
B. helping them match the background coloration of the habitat
C. stimulating production of killer T lymphocytes
D. repairing damage to the body wall