Bidirectional Enhancing Activities between Human T Cell Leukemia-Lymphoma Virus Type I and Human Cytomegalovirus in Human Term Syncytiotrophoblast Cells Cultured in Vitro

Ferenc D. Tóth, George Aboagye-Mathiesen, Judit Szabó, Xiangdong Liu, Xiangdong Liu, Jolàn Kiss, Henrik Hager, Milan Zdravkovic, Istvàn Andirkó, Jànos Aranyosi, Peter Ebbesen

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The syncytiotrophoblast layer of the human placenta has an important role in limiting transplacental viral spread from mother to fetus. Human cytomegalovirus (HCMV) is capable of establishing a latent infection in syncytiotrophoblast cells, with restriction of gene expression to immediate-early and early proteins. We analyzed the extent of replication of human T cell leukemia-lymphoma virus type I (HTLV-I) in human term syncytiotrophoblasts infected with HTLV-I alone or coinfected with HTLV-I and HCMV. Although syncytiotrophoblasts could be infected with cell-free HTLV-I, no viral protein expression was found in the singly infected cells. On the contrary, coinfection of the cells with HTLV-I and HCMV resulted in simultaneous replication of both viruses. Bidirectional enhancing activities between HTLV-I and HCMV were mediated primarily by the Tax and immediate-early proteins, respectively. The stimulatory effect of HTLV-I Tax on HCMV replication appeared to be mediated partly by tumor necrosis factor β and transforming growth factor β-1. We observed formation of pseudotypes with HTLV-I nucleocapsids within HCMV envelopes, whereas HCMV was not pseudotyped by HTLV-I envelopes in dually infected syncytiotrophoblast cells. Our data suggest that in vivo dual infection of syncytiotrophoblast cells with HTLV-I and HCMV may facilitate the transplacental transmission of both viruses.

Original languageEnglish
Pages (from-to)1495-1507
Number of pages13
JournalAIDS Research and Human Retroviruses
Issue number12
Publication statusPublished - Dec 1995


ASJC Scopus subject areas

  • Immunology
  • Virology
  • Infectious Diseases

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