HIV attacks macrophages first when it gains entry into a human body. After gaining entry into the body of the person, the virus enters into macrophages, where RNA genome of the virus replicates to form viral DNA with the help of the enzyme reverse transcriptase. The macrophages continue to produce virus particles, which enter the T-lymphocytes, replicate and form progeny virus. The progeny viruses are released in blood and attack other helper T-cells with result their number goes on decreasing infected person. This fall in the number of T-ceils causes immunodeficiency in the body. In such a condition the infected person is unable to protect himself from any type of infection.
