This scanning-electron micrograph shows human immunodeficiency virus (HIV-1) particles in green on the surface of a lymphocyte, a cell that plays a key role in the human immune system. Centers for Disease Control and Prevention photo by C. Goldsmith, P. Feorino, E.L. Palmer, W.R. McManus This scanning-electron micrograph shows human immunodeficiency virus (HIV-1) particles in green on the surface of a lymphocyte, a cell that plays a key role in the human immune system. Centers for Disease Control and Prevention photo by C. Goldsmith, P. Feorino, E.L. Palmer, W.R. McManus SHARE: Download: Full Size (5.18 MB) Credit: VIRIN: 452064-B-UPR01-769.jpg Photo Gallery