Describe how HIV is transmitted and how immune system cells in an infected person are affected by HIV. What are the most effective means of preventing HIV transmission? Why is AIDS particularly deadly compared with other viral diseases?

What is one of the differences between CD4⁺ and CD8⁺ T cells?

a. CD4⁺ cells are immature, and CD8⁺ cells are mature.

b. CD4⁺ cells are activated, and CD8⁺ cells are not.

c. CD4⁺ cells interact with class II MHC proteins, and CD8⁺ cells interact with class I MHC proteins.

d. CD4⁺ cells activate cell-mediated responses, and CD8⁺ cells activate humoral responses.

Which of the following should be the same in identical twins?

a. The set of antibodies produced

b. The set of MHC molecules produced

c. The set of T cell antigen receptors produced

d. The set of immune cells eliminated as self-reactive

Cytotoxic T cells are able to recognize infected body cells because

a. The infected cells display foreign antigens.

b. The infected cells produce antigens.

c. Infected cells release antibodies into the blood.

d. Helper T cells destroy them first.

Explain how gene recombination leads to the production of vast numbers of different B-cell receptors.

What steps are required for most B cells to become fully activated and differentiate into plasma cells?

Why is clonal selection necessary for the adaptive immune response but not the innate immune response? Select True or False for each statement.

T/F The adaptive immune response uses receptors to recognize pathogens, and the innate immune response does not.

T/F There is more receptor diversity in the adaptive immune response than in the innate immune response.

T/F Cells in the innate immune response do not require activation, and those in the adaptive immune response do.

T/F Clonal selection is used for targeting pathogens, and the innate immune response is used only to stop blood flow from the wound.

What would a vaccine have to contain to protect a patient from chicken pox? Explain why we don't have vaccines for HIV.