Human immunodeficiency virus type I Nef independently affects virion incorporation of major histocompatibility complex class I molecules and virus infectivity.
We have recently reported that HIV-1 Net down-regulates the cell surface expression of major histocompatibility complex class I (MHC-I) molecules. MHC-I molecules are one of the predominant cellular proteins associated with HIV-1 virions. Wild-type or nef-mutated HIV-1 virions were analyzed by immunoelectronic microscopy and Western blot for particle-associated MHC-I molecules. The number of MHC-I molecules was significantly higher in HIV-1 virions produced in the absence of Nef than in wild-type virions, indicating that Nef affects the incorporation of MHC-I molecules into virions. Wild-type HIV particles have been shown to be more infectious than Nef- viruses. This difference was maintained when Nef+ and Nef virions devoid of MHC-I molecules were produced in Daudi-CD4 cells. Therefore, the enhancement of virion infectivity and the down-regulation of MHC-I represent independent biological properties of Nef.
Le Gall
S
S
Laboratoire Rétrovirus et Transfert Génétique, Institut Pasteur, Paris, France.
Prevost
M C
MC
Heard
J M
JM
Schwartz
O
O
D015536:Down-Regulation; D015693:Gene Products, nef / Q000502:physiology*; D015497:HIV-1 / Q000235:genetics* / Q000502:physiology; D006367:HeLa Cells; D015395:Histocompatibility Antigens Class I / Q000502:physiology* / Q000648:ultrastructure; D006801:Humans; D016253:Microscopy, Immunoelectron; D014771:Virion / Q000502:physiology* / Q000648:ultrastructure; D014774:Virulence / Q000502:physiology; D054311:nef Gene Products, Human Immunodeficiency Virus
D015693:Gene Products, nef; D015395:Histocompatibility Antigens Class I; D054311:nef Gene Products, Human Immunodeficiency Virus