| Term | Definition |
|---|
| HIV | Human Immunodeficiency Virus: retrovirus that causes AIDS |
| SIV | closely related Simian Immunodeficiency Virus that infects primates
|
| FIV | related Feline Immunodeficiency Virus |
| HTLV | Related Human T-cell Lymphotrophic Virus; retrovirus first mistaken to be cause of AIDS |
| AIDS | Acquired Immune Deficiency Syndrome: progressive condition of immunosuppressive disease characterised by rare opportunistic infections due to an impairment of host immune responses by HIV |
| Retrovirus | A virus whose genetic makeup (genome) is stored in RNA rather than in the DNA form typical of bacteria and cellular genomes |
| Reverse Transcriptase | Enzyme (polymerase) carried by and encoded within HIV viral particle; copies and translates HIV's viral RNA into DNA form which can then be made into more viral messenger RNA copies by host cell's RNA polymerase or incorporated into host cell DNA. |
| Azidothymidine (AZT) | Wellcome's inhibitor of reverse transcriptase, common drug widely used in AIDS therapy |
| RNA polymerase | Enzyme that copies RNA form of DNA template instructions |
| DNA polymerase | Enzyme that makes DNA copies of DNA during host cell replication |
| Replication | Process of copying of genetic information |
| messenger RNA | RNA form of genetic instructions committed to produce protein encoded by its sequence. |
| glycoprotein (gp) | Protein that is modified after translation from messenger RNA form by the addition of one or many sugar residues to specific amino acids within the protein |
| Translation | Action of converting messenger RNA code to equivalent protein sequence of amino acids within ribosomes of endoplasmic reticulum |
| gp160 | HIV coat glycoprotein composed of separate gp41 and gp120 glycoproteins |
| env | Retroviral HIV gene encoding coat glycoproteins |
| gag | Another HIV 'master' gene encoding amongst other things viral core proteins |
| pol | Third HIV 'master' gene encoding reverse transciptase |
| core proteins | Proteins that form core shell of HIV which protects and shields RNA genome |
| protease | Viral enzyme that cleaves long precursor proteins into shorter functional ones |
| protease inhibitor | Drug that inhibits enzymatic action of HIV's protease |
| triple viral therapy | Strategy of using three different drugs to inhibit diverse processes within HIV life-cycle |
| CD4 receptor | HIV's target receptor found upon CD4-bearing lymphocyte which is primary mechanism for viral entry into cells via viral docking mechanism with gp120. |
| CD4 lymphocyte | 'White' blood cell bearing CD4 receptor that is primary target for HIV and a dramatic collapse in whose numbers heralds the onset of AIDS. CD4+ cells are also known as T4-helper lymphocytes and are involved in the amplification of a cellular immune response. |
| fusion | Process by which HIV enters CD4+ (bearing) cells by means of a complex structural rearrangement of gp160 and CD4 proteins after association and this drives the subsequent merging of the host cell and viral membranes, propelling HIV core into cell interior. |
| syncytium | Giant white blood cells formed after multiple fusion events with HIV. Such giant cells quickly die. |
| Long terminal repeats (LTR's) | Promoter region at either end of viral genome that facilitates both insertion of the viral genome into host DNA and also drives copying of virus' instructions from DNA template to messenger RNA form. |
| Error rate | Frequency of mistakes, or errors, in copying of HIV's genetic instructions. Reverse transcriptase has an unusually high error rate in copying HIV's genetic instructions. |
| Hypermutability | High frequency of mutations introduced into genetic instructions (esp.HIV), a characteristic flaw of reverse transcriptase |
| vaccine | Use of whole live, attenuated virus or component viral proteins as a trigger for a subsequent host humoral and cellular response to later infection by a virus bearing a closely-related set of recognisable antigenic features (epitopes). |
| delta 32 | Mutation arising in Europe on CCR5 receptor which confers resistance to HIV entry and subsequent proliferation |
| CCR5 | A chemokine receptor present upon white blood cells and port of entry for HIV and plague bacillus, recently described as co-receptor for entry of macrophage-tropic strains of HIV-1 |
| Interleukin-2 (IL-2) | Key chemokine which stimulates substantial and sustained increases of CD4 cells, a measure of immune competency |
| Chemokine | Hormone with biological activity or mediating communication function within cellular immune system |
| Tat | HIV protein which disrupts accessory-cell function and partially activates T cells, marking them for elimination by apoptosis (programmed cell death) |
| Rev | The major role of rev, another HIV protein, is to regulate the expression of HIV proteins by controlling the export rate of mRNAs |
| Vif | HIV-1 viral infectivity factor (Vif) is one of six regulatory proteins encoded by HIV-1 {Tat, Rev, Nef, Vpu and Vpr, essential for virus replication |
| Nef | Nef protein helps to prolong the life of its infected host cell while simultaneously destroying the neighboring uninfected cells of the immune system, partly by binding to and inhibiting the ASK1 apoptosis protein |
| Vpu | Vpu protein is required for the efficient assembly and release of new HIV viruses |
| Vpr | HIV-1 protein required for efficient viral propagation in vivo and arrests growth and division of infected host cell. Vpr also inhibits immune responses, induces the programmed cell death (apoptosis) of T cells and may help preserve antigen-stimulated T cells as viral proliferation reservoirs |
AIDS: Glossary of key definitions