The vpr protein (p14) arrests cell division at G2/M. The nef protein (p27) down-regulates CD4 (the major viral receptor), as well as the MHC class I and class II molecules.
A proteína Vpr (p14) detén o ciclo de división celular en G2/M. A proteína Nef (p27) regula á baixa o CD4 (o principal receptor viral), e as moléculas do MHC de clase I e de clase II.