Question

With the aid of a diagram, explain how the human immunodeficiency virus genome mutates during its replicative cycle to evade the host immune response.

Answer 1

The main place where the HIV genome gets mutated to change the host immume response is by reverse transcription and integration ( step 3&4 in the above figure )

Reverse transcription: In the host CD4 ⁺ cell HIV enters and uses reverse transcriptase to convert its RNA ,genetic material into HIV DNA which allows the HIV to enter the CD4 cell nucleus and combined with the cell DNA. This is the major step where HIV mutated its RNA genome to invade the host cell and affects its immune response.

Integration: Inside the host CD4 cell nucleus HIV releases integrase enzyme to insert its viral DNA into the DNA of CD4 ⁺ cell. Then assembly and budding happens which results in newly formed immature HIV and protease helps in formation of matured HIV virus. The cycle continues and many matured HIV virus forms inside the host cell and it results in depletion of CD4 ⁺ count which affects the host immune response and leads to formation of Acquired Immuno Deficiency syndrome.