Low level of BST-2 has been detected in Mechlorethamine hydrochloride macrophages and therefore could be the reason of Env accumulation at cell surface causing cell-cell fusion or syncytium formation. Finally, our data corroborated the finding that the restoration of infectivity of L30E viruses by inactivation of Vpu is a universal phenomenon that is occurring in labadapted as well as primary cells. We also confirmed that this phenomenon was not the characteristic feature of HIV-1 AD8 Env, as similar results were obtained after co-transfection of pNL-AD8Denv backbone with primary Envs of different clades. One possible explanation that could be offered for this phenomenon is that apart from CD4 degradation, Vpu may also be acting at the plasma membrane and participating in the assembly events of the virus. Recently the presence of Vpu in lipid rafts, considered to be potential sites of virus assembly and release was shown. The N-terminal MA domain of Gag is critical for membrane binding and was reported to be Vpuresponsive. It may 
be possible that at plasma membrane Vpu regulates the incorporation of Env on budding virus particles and this activity of Vpu is dependent on MA domain of Gag. Therefore, specific mutation in the MA domain of Gag might alter Vpu’s ability to regulate Env trafficking to virus budding sites. Various studies suggested that in Ginsenoside-F2 absence of Vpu, virion particles have been found both at plasma membrane and in internal vesicles similar to late endosomes. It was demonstrated that these virion particles that are found in internal vesicles are fully matured virus particles that have been targeted to these sites via en route from plasma membrane. It was clearly demonstrated by Pelchen-Mathhews et.al., that HIV buds from internal vesicles, also known as micro-vesicular bodies from monocytederived macrophages. Their immunolabeling experiments suggested that virions observed in intracellular vesicles possessed significant amount of Env as observed through anti-Env antibody staining, indicating that Env is enriched on these budding virions. But how these Envs are sorted into late endosomes budding structures is not known. The presence of high amount of Env on virions assembling into late endosomes suggests that these particles are likely to be infectious. Another study by Joshi et al., also suggested that intracellular compartments are capable of serving as sites for productive assembly in MDMs and T cells. Further studies are necessary to understand how MA domain of Gag is important for regulatory role of Vpu in HIV-1 Gag and Env trafficking. It will be important to determine whether Vpu diverts Gag and Env to the site of virus assembly or Gag MA determines the site of action of Vpu to participate in formation of infectious virions. Overall, our results demonstrated Vpu as a regulator of HIV-1 Gag assembly and Env incorporation. Our study provided new insight into the molecular mechanism regulating HIV-1 infectivity, Env incorporation during virus assembly and production of infectious virion particles from cell lines and physically relevant cell-types, like PBMC and monocyte-derived macrophages. We speculate that two viral proteins, Gag and Vpu together with various cellular factors play an important role in determining the site of virus release and formation of infectious virus particles. Further studies are required to understand the detailed mechanism of Gag and Env trafficking and to delineate the intracellular transport steps affected by Vpu at the time of HIV-1 assembly. Such information would likely provide comprehensive understanding on the mechanism of assembly and Env incorporation during HIV-1 morphogenesis.