Final answer:
The CCR5Δ32 mutation (option 1) is associated with decreased susceptibility to HIV infection by preventing the virus from effectively binding and entering the host T cell.
Step-by-step explanation:
Mutation Associated with Decreased Susceptibility to HIV Infection
The mutation associated with decreased susceptibility to HIV infection is CCR5Δ32 (option 1). CCR5 is a receptor on the surface of T cells that HIV typically uses to enter these immune system cells. The Δ32 mutation results in a receptor that HIV cannot effectively bind to, thus inhibiting the virus's entry into the host cell and conferring resistance to those who are homozygous for this mutation and providing some degree of protection to heterozygous individuals.
Inhibition of HIV Life Cycle
Individuals with the CCR5Δ32 mutation experience an inhibition in the early stage of the HIV life cycle, which is the virus's entry into the host T cell. The stage of entry requires both the CD4 receptor and a co-receptor, usually CCR5. Without a functional CCR5 receptor due to the Δ32 mutation, the virus cannot effectively initiate infection, leading to the resistance observed in homozygous carriers of the mutation. This exciting discovery has paved the way for new anti-HIV drug development strategies focusing on inhibiting the binding of HIV to CCR5.
It is essential to understand that despite the protective effects of the CCR5Δ32 mutation, there have been cases where individuals homozygous for the mutation have contracted HIV. Therefore, relying solely on this genetic trait to prevent infection is not recommended, and public health officials do not endorse DNA testing for this mutation as a means to encourage risky behaviors.
In conclusion, the correct option for the mutation associated with decreased susceptibility to HIV infection is option 1, CCR5Δ32.