Question

HIV, the virus which causes AIDS, interacts with two receptors on the host cell membrane: CD4 and CCR5. A small percentage of individuals have a genetic mutation which causes their cells to lack CCR5. These individuals will never develop AIDS nor are they able to pass HIV on to others. Which part of viral replication is being blocked by the lack of a receptor? Select one: o a. Newly assembled virions cannot be released from the host cell. O b. Endocytosis is being prevented. o c. The virus components cannot be assembled into new virions. o d. The host cell enzymes are unable to replicate the HIV genome. o e. HIV cannot attach to the host cell without the proper membrane receptor.

Answer 1

The answer is e. HIV cannot attach to the host cells without membrane receptors.

Explaination:

CCR5 receptor is a chemokine receptor type 5. It is present on cell surface and used by HIV to infect the host cells.

It is said to be a primary coreceptor which is used by gp120 membrane receptor of HIV along with CD4.

Thus, It is used to fuse virus membrane to the host cell membrane during the entry of virus.

The mutation in CCR5 receptor, called as CCR5 delta 32 mutation, in host cell prevents HIV from entering into host cell.

The research is going on to target CCR5 receptor for the treatment of AIDS because mutations in this receptor is known to induce the resistance to HIV infection by preventing the early stage infection of viruses to host cells.