%0 Journal Article
%T HIV-1 Trans Infection of CD4+ T Cells by Professional Antigen Presenting Cells
%A Charles R. Rinaldo
%J Scientifica
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/164203
%X Since the 1990s we have known of the fascinating ability of a complex set of professional antigen presenting cells (APCs; dendritic cells, monocytes/macrophages, and B lymphocytes) to mediate HIV-1 trans infection of CD4+ T cells. This results in a burst of virus replication in the T cells that is much greater than that resulting from direct, cis infection of either APC or T cells, or trans infection between T cells. Such APC-to-T cell trans infection first involves a complex set of virus subtype, attachment, entry, and replication patterns that have many similarities among APC, as well as distinct differences related to virus receptors, intracellular trafficking, and productive and nonproductive replication pathways. The end result is that HIV-1 can sequester within the APC for several days and be transmitted via membrane extensions intracellularly and extracellularly to T cells across the virologic synapse. Virus replication requires activated T cells that can develop concurrently with the events of virus transmission. Further research is essential to fill the many gaps in our understanding of these trans infection processes and their role in natural HIV-1 infection. 1. Introduction The uptake of human immunodeficiency virus 1 (HIV-1) by professional antigen presenting cells (APCs) and subsequent transfer of virus to CD4+ T cells can result in explosive levels of virus replication in the T cells. This could be a major pathogenic process in HIV-1 infection and development of acquired immunodeficiency syndrome (AIDS). This process of trans (Latin; to the other side) infection of virus going across from the APC to the T cell is in contrast to direct, cis (Latin; on this side) infection of T cells by HIV-1. Note that this is a narrow definition of trans infection, as direct, cell-to-cell spread of virus is a classic phenomenon in viral infections [1], including HIV-1 [2, 3]. In fact, T cell-to-T cell infection involves many factors that are part of APC-to-T cell trans infection, including expression of CD4 on T cells and formation of a virologic synapse [4, 5] and evasion of neutralizing antibody [6] and the viral inhibitory effects of antiretroviral treatment (ART) [7, 8]. The use of trans infection in this review, however, refers to the in vitro model where infection of APC with low levels of HIV-1 leads to replication of virus in T cells, that is, orders of magnitude more than cis infection of either APC or T cells, and T cell-to-T cell or APC-to-APC trans infections. The outcome of the APC-to-T cell trans infection process has been considered to be
%U http://www.hindawi.com/journals/scientifica/2013/164203/