Particle - of a virus, a virion or one complete copy of a virus. Corresponds to a cell or bacterium. Protease - an enzyme used by viruses to build the protein coat of the completed virus core. PTI - protease inhibitor. Resistance - the ability of a virus to reproduce in the presence of a drug that should block reproduction.
Resistance usually arises because of a mutation of the virus.
HIV contains RNA rather than DNA as most other viruses do. Reverse Transcriptase - an enzyme utilized by HIV to reproduce by the production of DNA from the RNA carried by the virus. Since reverse transcriptase is not a component of normal human cells, it is an obvious target for Anti-HIV therapy. Surrogate markers - clinical results which are used as a substitute for other events, such as using CD4 counts or viral load as a measure of a drugs efficacy instead of following patients to the point of death or other undesirable result. Viral load - the measured concentration of HIV in the bloodstream.