Thus, the gp41 HR1 region contributes to the association with gp120 and regulates Env transitions from the unliganded state to downstream conformations.<b>IMPORTANCE</b> The development of an efficient vaccine able to prevent HIV infection is a worldwide priority.
An important step in human immunodeficiency virus infection involves the interaction between the viral envelope glycoprotein gp120 and the human host cell surface receptor CD4.
Short interfering RNA knockdown of endogenous UNG2 in primary cells showed that UNG2 is required for R5 but not X4 HIV infection and that this requirement is bypassed when HIV enters the target cell via vesicular stomatitis virus envelope-glycoprotein-mediated endocytosis.
Enfuvirtide (T-20) is the first entry inhibitor approved for treatment of HIV infection and acts by inhibiting conformational changes in the viral envelope protein gp41 that are necessary for fusion of the virus and host cell membranes.
In addition, the alpha chemokine SDF1alpha and the beta chemokines MIP1alpha, MIP1beta, and RANTES, natural ligands of CXCR4 and CCR5, respectively, are potent soluble inhibitors of HIV infection by blocking the binding between the viral envelope glycoprotein gp120 and the coreceptors.
Susceptibility of cells to HIV infection is correlated with CD26 expression, and HIV transactivator Tat and envelope protein gp120 are reported to interact with CD26.