Multiple recombinant events in human T-cell Leukemia virus Type 1: complete sequences of recombinant African strains

Olivier Cassar (1, 2) , Alexandra Desrames (2) , Ambroise Marçais (3) , Olivier Gout (4) , Graham Taylor (5) , Olivier Hermine (3) , Vicente Soriano (6) , Carmen De Mendoza (7) , Océane Dehan (2) , Margot Le Mener (2) , Philippe Afonso (2) , Antoine Gessain (2)

1 IP - Institut Pasteur [Paris]
2 EPVO (UMR_3569 / U-Pasteur_3) - Epidémiologie et Physiopathologie des Virus Oncogènes / Oncogenic Virus Epidemiology and Pathophysiology
3 Service d'hématologie [CHU Necker]
4 Fondation Ophtalmologique Adolphe de Rothschild [Paris]
5 Imperial College London
6 UNIR - Universidad Internacional de la Rioja
7 Puerta de Hierro Majadahonda University Hospital

Africa is the largest endemic area for HTLV-1, with many molecular genotypes. We previously demonstrated that some strains from North Africa (a-NA clade) originated from a recombinant event between Senegalese and West African strains. A series of 52 new HTLV-1 strains from 13 North and West African countries were sequenced in the LTR region and/or a env gene fragment. Four samples from French Guyanese of African origin were also added. Furthermore, 7 complete sequences from different genotypes were characterized. Phylogenetic analyses showed that most of the new African strains belong to the Cosmopolitan a-genotype. Ten new strains from the a-NA clade were found in Morocco, Western Sahara, Mali, Guinea, Côte d'Ivoire and Ghana. A new a-G-Rec clade, which arose from a distinct recombination event between Senegalese and West African strains, was identified in Guinea and Ghana. The complete sequences suggest that recombination occur in the LTR as well as the env/pol region of the genome, thus a-NA and a-G-Rec strains have a mosaic profile with genetic segments from either a-WA or a-Sen strains. Our work demonstrates that recombination in HTLV-1 may not be as rare an event as previously proposed.

Mots clés: Africa; HTLV-1; HTLV-1 complete genome; molecular epidemiology; recombination; reverse transcription

Domaines: Sciences du Vivant [q-bio]

Olivier Cassar, Alexandra Desrames, Ambroise Marçais, Olivier Gout, Graham Taylor, et al.. Multiple recombinant events in human T-cell Leukemia virus Type 1: complete sequences of recombinant African strains. Emerging microbes & infections, 2020, 9 (1), pp.913-923. ⟨10.1080/22221751.2020.1752117⟩. ⟨pasteur-03208018⟩