Select the correct statements from the following : 

a- HIV enters into helper T-lymphocytes (T_H), replicates and produce progeny viruses.

b- A widely used diagnostic test for AIDS is enzyme linked immuno-sorbent assay (ELISA).

c- Treatment of AIDS with anti-retroviral drugs is only partially effective.

a,b and c

HIV enters into helper T-lymphocytes (T_H), replicates and produce progeny viruses. The progeny viruses released in the blood attack other helper T-lymphocytes. This is repeated leading to a progressive decrease in the number of helper T- lymphocytes in the body of the infected person .

A widely used diagnostic test for AIDS is enzyme linked immuno-sorbent assay (ELISA).

Treatment of AIDS with anti-retroviral drugs is only partially effective. They can only prolong the life of the patient but cannot prevent death, which is inevitable.