A protein located on or in a cell, which recognises and binds to a specific type of molecule.

As related to HIV: Three regulatory HIV genes � tat, rev, and nef � and three so-called auxiliary genes � vif, vpr, and vpu � contain information for the production of proteins that regulate the virus' ability to infect a cell, produce new copies of the virus, or cause disease.

T cells that direct other immune cells to perform special functions. The chief regulatory cell, the CD4+ T cell or T helper cell, is HIV's chief target.

Viral reproduction. Viruses do not reproduce sexually; instead they multiply inside the host cell by budding, making perhaps millions of copies of themselves each day in the lymphocytes of an infected person.

The ability of a virus to resist the effects of antiviral drugs intended to stop its replication.

Condition in which a portion of the retina becomes separated from the inner wall of the eye. In AIDS patients, it can result from retinal disease such as CMV retinitis. The condition can rapidly lead to vision loss but is treatable by adding silicone to the eye's vitreous humor to increase the pressure on the retina.

Inflammation of the retina, linked in AIDS to cytomegalovirus (CMV; see) infection. If untreated, it can lead to blindness.

A virus whose genes are carried as RNA and which converts RNA to DNA to enable it to integrate with the host cell DNA.

The process of making cDNA (complementary DNA) transcription using an RNA template. An essential step in PCR for retroviruses, e.g. HIV.

A retrovirus enzyme that synthesises DNA from RNA.

Synthesis of DNA from RNA. Occurs naturally in retroviruses. In other organisms RNA is synthesised from DNA.

Ribonucleic acid. In most organisms, the molecule that 'translates' the information coded by DNA into proteins. In some viruses, such as HIV, the codes (genes) themselves are carried in RNA.

Recombinant thermostable DNA Polymerase originally isolated from the bacterium Thermus thermophilus. rTth has optimal activity at 70-80 C and survives the denaturation steps of PCR. In addition to DNA Polymerase activity, it has efficient reverse transcriptase activity in the presence of manganese.