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ArticleCopyright
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Embargo date
2021-01-08
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- INI - Artigos de Periódicos [3645]
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HIGH FREQUENCIES OF FUNCTIONALLY COMPETENT CIRCULATING TAX-SPECIFIC CD8+ T CELLS IN HUMAN T LYMPHOTROPIC VIRUS TYPE 2 INFECTION
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Abstract
Human T lymphotropic virus type 2 (HTLV-2) is characterized by a clinically asymptomatic persistent infection in the vast majority of infected individuals. In this study, we have characterized for the first time ex vivo specific CTL responses against the HTLV-2 Tax protein. We could detect CTL responses only against a single HLA-A*0201-restricted Tax2 epitope, comprising residues 11–19 (LLYGYPVYV), among three alleles screened. Virus-specific CTLs could be detected in most evaluated subjects, with frequencies as high as 24% of circulating CD8 T cells. The frequency of specific CTLs had a statistically significant positive correlation with proviral load levels. The majority of virus-specific CD8 T cells exhibited an effector memory/terminally differentiated phenotype, expressed high levels of cytotoxicity mediators, including perforin and granzyme B, and lysed in vitro target cells pulsed with Tax2 (11–19) synthetic peptide in a dose-dependent manner. Our findings suggest that a strong, effective CTL response may control HTLV-2 viral burden and that this may be a significant factor in maintaining persistent infection and in the prevention of disease in infected individuals.
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