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  • Oral presentation
  • Open Access

Deep sequencing of the TCRβ repertoire reveals T cell clonal expansion is associated with HTLV-1 proviral load in HAM/TSP patients

  • 1,
  • 2,
  • 1,
  • 3,
  • 4 and
  • 1Email author
Retrovirology201512 (Suppl 1) :O21

https://doi.org/10.1186/1742-4690-12-S1-O21

  • Published:

Keywords

  • Clonal Expansion
  • Proviral Load
  • Inflammatory Central Nervous System
  • CDR3 Sequence
  • Cell Clonal Expansion

HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP) is associated with a chronic inflammatory central nervous system in which the host immune response against HTLV-1 infection is considered immunopathogenic. We have applied a new unbiased deep sequencing method of TCR repertoire to accurately measure the diversity and degree of clonal expansion of peripheral circulating T-cells in patients with HAM/TSP compared to age, gender, and ethnicity matched healthy controls. TCR libraries were generated using 5'rapid amplification of cDNA ends to amplify the V-D-J genes of unsorted T-cells obtained from peripheral blood. Over 100 million reads were analyzed using MiGec software (Shugay, et al., Nat Methods. 2014 Jun;11(6):653-5), that align and match the human TCR β-chain nucleotide sequences through IMGT database. T-cell clonotypes with high-quality CDR3 sequence were selected by a molecular identifier PCR strategy, which allowed for filtering PCR errors and correct for artificial sequences generated on a HiSeq 2000 Illumina system platform. By calculating the coefficient of variation of our dataset we considered clonal expansion as those unique TCR clonotypes showing reads >8. While we did not observe any significant statistical differences of the number of single clones (clonotypes with 1 read, P=0.62) between HAM/TSP patients and healthy controls groups, by contrast, a higher clonal expansion of the T-cell repertoire was observed in HAM/TSP patients when compared to healthy controls (unpaired parametric T-test with P=0.026). Interestingly, this clonal expansion of the HAM/TSP TCR repertoire correlated with the HTLV-I provirus load (as defined by digital PCR quantification of the HTLV-I tax gene) (r=0.64, P=0.008). Our findings strongly suggest that in this chronic neurological disorder, a strong dysregulated T-cell response may be driven by HTLV-I and that strategies to decrease virus may be of clinical benefit.

Authors’ Affiliations

(1)
Neuroimmunology Branch, Viral Immunology Section, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, Maryland, USA
(2)
Bioinformatics Section, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, Maryland, USA
(3)
Systems Biology Center, National Heart Lung and Blood Institute, Bethesda, Maryland, USA
(4)
Division of Brain Sciences, Faculty of Medicine, Imperial College London, UK

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