Abstract
Patas monkeys were not reported to carry species‐specific simian immunodeficiency virus (SIV), but cross‐species transmission of SIVagm to patas monkeys occurred in the wild. We report that patas monkeys share immunophenotypic features with natural hosts of SIV; that is, low levels of CD4+ T cells and low CCR5 expression on CD4+ T cells. In 1 patas monkey with undetectable levels of CD4+ T cells, experimental exposure to SIVagm did not result in infection. The other experimentally infected patas monkeys showed an infection pattern similar to SIV infection in natural hosts. Thus, down‐regulation of CD4 and CCR5 expression on CD4+ T cells may effectively control human immunodeficiency virus acquisition and result in SIV extinction.