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  • Open Access

ORFI genetic polymorphisms in geographically distinct HTLV-1 infections

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Retrovirology201512 (Suppl 1) :P55

  • Published:


  • Infectious Disease
  • Cancer Research
  • Virus Infectivity
  • Clinical Manifestation
  • Genetic Polymorphism

The region known as pX in the 3’ end of the human T-cell leukemia/lymphoma virus type-1 (HTLV-1) genome contains four overlapping open reading frames (ORF) that encode regulatory proteins. The expression of ORF-I produces the protein p12 which can be cleavage resulting in the p8 protein. These proteins interfere with the ability of a biologically active of HTLV-1, influencing at the virus infectivity and persistence. Here, we evaluated whether natural mutations in HTLV-1 ORF-I can influence the proviral load and clinical manifestation of HAM/TSP. For that, we analyzed 1530 HTLV-1 ORF-I sequences from different clones of 156 patients with negative or positive diagnosis for HAM/TSP and demonstrated that some mutations may be associated with the outcome of HAM/TSP (C39R, L40F, P45L, S69G and R88K) or with proviral load (P34L and F61L). We further examined the presence of mutations in motifs of HBZ and observed that P45L mutation is located within the HBZ nuclear localization signal and was found more frequently between patients with HAM/TSP and high proviral load. This results suggest that some HTLV-1 ORF-I mutations may be associated with the development of HAM/TSP and the proviral load levels.

Authors’ Affiliations

Centro de Pesquisa Gonçalo Moniz-Fiocruz, Salvador, Bahia, Brazil
Escola Bahiana de Medicina e Saúde Pública, Salvador, Bahia, Brazil
Animal Models and Retroviral Vaccines Section, National Cancer Institute, Bethesda, USA
Department of General and Experimental Pathology, Medical University of Białystok, Poland
Unité d'Epidémiologie et Physiopathologie des Virus Oncogènes, Département de Virologie, Batiment Lwoff, Institut Pasteur, Paris, France
Viral Immunology Section, Neuroimmunology Branch, National Institute of Neurological Disorders and Stroke, Bethesda, USA


© Barreto et al. 2015

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated.