T Cell Polarization and the Formation of Immunological Synapses: From Antigen Recognition to Virus Spread

Abstract

Soon after antigen recognition, T lymphocytes polarize towards antigen presenting cells (APC) and form immunological synapses. The formation of immunological synapses is a complex process that involves T cell signaling, as well as membrane, cytoskeleton and vesicular trafficking events. Immunological synapses are thought to be multitasking molecular arrangements that structure in time and space the complex communication between T lymphocytes and APCs. Lymphotropic viruses, such as the human immunodeficiency virus (HIV), or herpes virus saimiri can impede the formation and function of immunological synapses hence downregulating the capacity of response of infected T lymphocytes. Moreover, retroviruses, like HIV-1, or the human T cell leukemia virus type 1 (HTLV-1), can subvert the mechanism of T cell polarization and immune synapse formation to form organized cell junctions through which these viruses can spread from cell to cell. By analogy to immunological synapses, these viral-induced cell-cell junctions have been called virological synapses. The understanding of the mechanism of generation of immunological synapses versus virological synapses is a fascinating field of study that we will discuss in this review. Keywords: microtubule organizing center, antigen presenting cells, WASP-interacting protein, Herpesvirus Saimiri, Lymphotropic viruses