Chapter 45

Which of the following most accurately describes mammal defenses against disease-causing viruses or organisms? a. The three lines of defense work independently of each other in defending against a particular pathogen. b. Physical barriers are part of the immune system. c. The adaptive immune system reacts faster to pathogens than the innate immune system. d. Once the adaptive immune system is activated in response to a specific pathogen, the innate immune system stops functioning against that specific pathogen. e. White blood cells are key participants in adaptive immunity but not innate immunity.

Which of the following is not a component of the inflammatory response? a. macrophages b. neutrophils c. B cells d. mast cells e. eosinophils

When a person's immune system resists infection by a pathogen after being vaccinated against it, this is the result of: a. innate immunity. b. immunological memory. c. a response with defensins. d. an autoimmune reaction. e. systemic inflammation.

One characteristic of a B cell is that it: a. has the same structure in both invertebrates and vertebrates. b. recognizes antigens held on class I major histocompatibility complex proteins. c. binds virus-infected cells and kills them directly. d. makes many different B-cell receptors on its surface. e. has a B-cell receptor on its surface, which is the IgM molecule.

An antigen-presenting cell: a. can be a CD8 + T cell. b. derives from a phagocytic cell and exposes an antigen to a lymphocyte. c. secretes antibodies. d. cannot be a B cell. e. cannot stimulate helper T cells.

After Sally punctured her hand with a dirty nail, she received both a vaccine and someone else's antibodies against tetanus toxin. The immunity conferred here is: a. both active and passive. b. active only. c. passive only. d. first active; later passive. e. innate.

Drugs are administered to patients to enhance the immune response when treating: a. organ transplant recipients. b. anaphylactic shock. c. rheumatoid arthritis. d. HIV infection. e. type I diabetes.

HIV wreaks havoc with the immune system by attacking helper \(\mathrm{T}\) cells and macrophages. Would the impact be altered if the virus attacked only macrophages? Explain.

Given what you know about how foreign invaders trigger immune responses, explain why mutated forms of viruses, which have altered surface proteins, pose a monitoring problem for memory cells.

Space, the final frontier! Indeed, but being in space causes some problems. Astronauts in space show a decline in their ability to mount an immune response and, consequently, develop a decreased resistance to infection. Two potentially important differences in physiology in space versus on Earth are more fluid flowing to the head and a lack of weight bearing on the lower limbs. Could they be involved somehow in the deleterious effect on the immune system? Design an experiment to be done on Earth to answer this question.

Defensins are found in a wide range of organisms, including plants as well as animals. What are the evolutionary implications of this observation?