HIV Type 1 Nef is released from infected cells in CD45(+) microvesicles and is present in the plasma of HIV-infected individuals.
HIV-1 Nef has been demonstrated to be integral for viral persistence, infectivity, and the acceleration of disease pathogenesis (AIDS) in humans. Nef has also been detected in the plasma of HIV-infected individuals and is released from infected cells. The form in which Nef is released from infected cells is unknown. However, Nef is a myristoylated protein and has been shown to interact with the intracellular vesicular trafficking network. Here we show that Nef is released in CD45-containing microvesicles. This microvesicular Nef (mvNef) is detected in the plasma of HIV-infected individuals at relatively high concentrations (10 ng/ml). It is also present in tissue culture supernatants of Jurkat cells infected with HIV(MN). Interestingly, plasma mvNef levels in HIV(+) patients did not significantly correlate with viral load or CD4 count. Microvesicular Nef levels persisted in the plasma of HIV-infected individuals despite the use of antiretroviral therapy, even in individuals with undetectable viral loads. Using cell lines, we found Nef microvesicles induce apoptosis in Jurkat T-lymphocytes but had no observed effect on the U937 monocytic cell line. Given the large amount of mvNef present in the plasma of HIV-infected individuals, the apoptotic effect of mvNef on T cells, and the observed functions of extracellular soluble Nef in vitro, it seems likely that in vivo mvNef may play a significant role in the pathogenesis of AIDS.
Raymond
A D
AD
Morehouse School of Medicine, Atlanta, Georgia 30310, USA.
Campbell-Sims
T C
TC
Khan
M
M
Lang
M
M
Huang
M B
MB
Bond
V C
VC
Powell
M D
MD
D017209:Apoptosis; D015693:Gene Products, nef / Q000378:metabolism*; D015658:HIV Infections / Q000097:blood* / Q000188:drug therapy; D015497:HIV-1 / Q000378:metabolism*; D006801:Humans; D019169:Jurkat Cells; D017493:Leukocyte Common Antigens / Q000378:metabolism*
D015693:Gene Products, nef; D017493:Leukocyte Common Antigens