HIV assembly ‐‐ The macrophage scenario

Abstract

The assembly of enveloped viruses in eukaryotic cells requires interaction with cellular membrane trafficking and protein sorting machineries. Structural proteins of the virus, and key cellular components, must be brought together in a spatially and temporally controlled manner to allow the formation of infectious virus particles. The human immunodeficiency virus (HIV‐1) is a particularly useful model for analysing these activities. The small genome, and the fact that only three virally encoded proteins are required for infectious particle formation, makes this virus an attractive model for cellular and biochemical analysis.We have studied the formation of HIV in human macrophages and find that particles assemble on the limiting membrane, and bud into the lumen, of an intracellularly sequestered plasma membrane domain. Viruses appear to be stored within this assembly compartment prior to release. This release may be induced when T cells interact with infected macrophages leading to the formation of so‐called (virological synapses) through which viruses are efficiently transferred to T cells. Characterisation of the assembly compartment will likely shed new light on the molecular basis of HIV assembly and provide insights to the ways in which these viruses exploit the properties of monocyte‐derived cells for efficient cell‐to cell transmission.