High frequency of viral protein expression in human T cell lymphotropic virus type 1-infected peripheral blood mononuclear cells.
Most human T cell lymphotropic virus type (HTLV)-1-infected individuals mount a strong and persistently activated cytotoxic T lymphocyte (CTL) response to the virus, which implies that there is abundant chronic transcription of HTLV-1 genes. On the other hand, several observations suggest that HTLV-1 might be latent in vivo and therefore not detectable by CTLs. To clarify these discrepancies, we quantified the frequency of provirus-positive peripheral blood mononuclear cells (PBMCs) that were capable of expressing the HTLV-1 Tax protein, which is known to be the immunodominant target antigen recognized by HTLV-1-specific CTLs. The analysis showed that a significant proportion of HTLV-1-infected cells (from 14 to 100%) starts to express the Tax protein within a few hours of culture ex vivo. Phenotypic analysis confirmed that the main cell subpopulation expressing the Tax protein is CD4 positive. Frequent Tax expression in CD4(+) T lymphocytes in vivo might account for the chronic activation of the cytotoxic immune response observed in the majority of HTLV-1-infected patients and might contribute to the pathogenesis of HTLV-1-associated diseases.
Hanon
E
E
Department of Immunology, Imperial College School of Medicine, St Mary's campus, London W21PG, United Kingdom.
Asquith
R E
RE
Taylor
G P
GP
Tanaka
Y
Y
Weber
J N
JN
Bangham
C R
CR
D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000821:virology*; D002353:Carrier State / Q000821:virology; D002478:Cells, Cultured; D016356:Gene Products, tax / Q000276:immunology / Q000378:metabolism*; D015368:Human T-lymphotropic virus 1 / Q000378:metabolism*; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000276:immunology / Q000821:virology*; D015493:Paraparesis, Tropical Spastic / Q000276:immunology / Q000821:virology; D010641:Phenotype; D011533:Proviruses / Q000378:metabolism*; D019562:Viral Load
D016356:Gene Products, tax