Mechanism of AIDS infection involves.
(i) After entering into the body of a person, the virus attacks the macrophages. Inside macrophages, the RNA genome of the virus replicates to form viral DNA with the help of enzyme reverse transcriptase.
(ii) The viral DNA gets integrated into the host cell’s DNA and uses the raw material and infected cell machinery to produce virus particles.
(iii) The macrophages continue to produce virus particles and act, like a HIV factory.
(iv) Simultaneously, virus enters the helper T-lymphocytes (Th). Where also, it replicates and forms progeny viruses.
(v) Progeny viruses released in the blood, attack the other helper T-lymphocytes, resulting in progressive decrease in their number in infected person. With the lack of T-lymphocytes, B-lymphocytes do not produce antibodies to encounter the pathogens/antigens.
(vi) Infected person becomes so immunodeficient that he/she is unable to protect himself/herself against any infection/pathogen such as Mycobacterium, viruses and even parasites like Toxoplasma.