C. CD4 downregulation
D. MHC class ii downregulation
E. Sustaining t-cell activation 13.12 Fill-in-the-Blanks: Human immunodeficiency virus (HiV) is a retrovirus that is classified as such because it contains a ____________ enzyme. it infects host cells via its envelope binding to the ________ receptor and either the _______ or _______ co-receptor. When an individual becomes infected, they mount an immune response that results in the production of anti-HiV antibodies, a process called __________. CD8+ t-cell responses are also generated, but HiV can acquire ________ that allow it to evade recognition by these Ctls.
13.13 Multiple Choice: Which of the following is not a genetic variant that reduces susceptibility to HiV infection or slows protections to aiDS?
A. Mutant CCR5 allele
B. Mutant CXCR4 allele
C. Certain Hla class i alleles
D. Possessing KiR3DS1 with certain Hla-B alleles 13-2 Primary immunodeficiency diseases are caused by inherited gene defects.
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13-3 Defects in T-cell development can result in severe combined immunodeficiencies.
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