An Anti‐CD45RO Immunotoxin Kills Latently Infected Human Immunodeficiency Virus (HIV) CD4 T Cells in the Blood of HIV‐Positive Persons

Highly active antiretroviral therapy has decreased the morbidity and mortality of human immunodeficiency virus (HIV) infection, but latently infected cells remain for prolonged periods. CD4(+) CD45RO(+) T cells are a major latent virus reservoir in HIV-infected persons. Replication-competent, latently HIV-infected T cells can be generated in vitro by infecting peripheral blood mononuclear cells with HIV and then eliminating the HIV-producing cells with an anti-CD25 immunotoxin (IT). The CD25(-) latently infected cells then can be eliminated with an anti-CD45RO IT. This study determined whether this IT also could kill latently infected CD4 T cells from HIV-infected persons with or without detectable plasma viremia. The results show that ex vivo treatment of cells from HIV-positive persons by anti-CD45RO IT reduces the frequency of both productively and latently infected cells. In contrast, CD4(+) CD45RA(+) naive T cells and a proportion of CD4(+) CD45RO(lo) memory T cells are spared.