Explain the process of replication of retrovirus after it gains entry into the human body.

Explanation

(i) After getting into the human body, the virus enters the macrophages.
(ii) Here the RNA genome of the virus replicate of form viral DNA. This is done with the help of enzyme reverse transcriptase.
(iii) The viral DNA gets incorporated into DNA of hosts cells and directs the infected cells to produce viral particles.
(iv) So the macrophages continue to produce virus.
(v) HIV also enters T-lymphocytes, replicate and produce progeny viruses.
(vi) The progeny viruses released in the blood attack other T-lymphocytes and the cycle repeats leading to a decrease in the number of helper T-lymphocytes.