Molecular level view gives immune system clues.
Marwick
C
C
D000163:Acquired Immunodeficiency Syndrome / Q000276:immunology*; D017977:Deltaretrovirus / Q000201:enzymology; D006801:Humans; D012194:RNA-Directed DNA Polymerase / Q000378:metabolism; D013601:T-Lymphocytes / Q000382:microbiology / Q000502:physiology*
D012194:RNA-Directed DNA Polymerase