What is the mechanism by which the AIDS virus cause deficiency of immune system of the infected person?

Explanation

(i) After getting into the body of the person, the HIV enters into macrophages where RNA genome of the virus replicates to form viral DNA with the help of reverse transcriptase enzyme. The viral DNA then gets incorportated into host cell's DNA to direct the synthesis of virus particles.
(ii) HIV also enters into helper T-lymphocytes. It replicates and produces viral progeny. These viruses are then released into the blood and attack other helper T-lymphocytes. In this way, there occurs progressive decrease in number of helper T-lymphocytes in the body of the infected person. Due to decrease in helper T-lymphocytes, person starts suffering from infections.