Antibodies: protein molecules secreted by B-cells that binds to a specific antigen.

Antigen: any substance that causes a reaction by the immune system.

CCR5 (or CC-CKR5): This is a receptor found embedded in the membranes of macrophages. It serves as a coreceptor that allows HIV to enter those cells.   Signaling molecules called chemokines also bind to this receptor.

CXCR3 (or fusin): This is a receptor found embedded in the membranes of T cells.

Chemokines: chemokines are signaling molecules that attract immune cells to infected cells.  Some examples of chemokines are MIP-1a, MIP-1b,and   RANTES. Chemokines have been found to bind to a corecptor for the HIVvirus that is on the surface of macrophages.

DNA: Deoxyribonucleic Acid. A type of genetic material that stores information in its unique base pairs. It consists of a phosphate/sugar backbone that curls around in a double helix pattern. The base pairs point toward the center of the helix. It is called deoxyribonucleic acid because the sugar in the backbone happens to be missing one oxygen.

Enveloped virus: Viruses with a membrane surrounding its protein coat

Glycoprotein 41 (gp-41): Protein on the outer coat of HIV that allows the virus to fuse with plasma membranes of host cells.

Glycoprotein 120 (gp-120): Protein on the coat of HIV that attaches to CD4 and coreceptors of host cells.

HIV: Human Immunodeficiency Virus - it is a virus that destroys key components of the immune system necessary for fighting off a variety of infections.

Integrase: HIV enzyme that catalyzes the insertion of HIV's DNA transcript into the nucleus and DNA of the infected cell.

Lymphocytes: white blood cells, such as B-cells and T-cells, that patrol the body for "non-self" tags.

Lysogenic cycle: Occurs when a virus inserts its genome into the host genome where it can lie dormant until certain outside factors cause the new genetic material to be transcribed.

Macrophage: Amoebid type of white blood cell that engulfs and digests foreign bodies.

Non-enveloped virus: Viruses that do not have a membrane surrounding its protein coat

reverse transcription: reverse transcription means to convert RNA to DNA.

retrovirus: A retrovirus is a virus that contains an RNA genome.  In order to allow its genetic material to insert into the host genome, the retrovirus performs reverse transcription to convert the RNA to DNA(it is called "retro-" because this process is performed backwards as compared to the way genetic material   is normally transcribed).

RNA: Ribonucleic acid. Another type of genetic material. This molecule helps to carry out the information stored in DNA by transcribing the DNA sequence and specifying which amino acids should make up the protein being constructed.   This molecule is often single stranded with a phosphate/sugar backbone and base pairs.

T-cells: white blood cells that mature in the thymus.  Their job is to help organize or directly participate in the immune defenses.

Translocation: Method by which non-enveloped viruses invade a cell.   Method relates to the receptor mediated endocytosis.

Tropism: The tendency of a pathogen to infect specific types of tissues.