Effects of HIV-1 Tat on expression of HLA class I molecules

Masanori Matsui, Robert J. Warburton, Patricia C. Cogswell, Albert S. Baldwin, Jeffrey A. Frelinger

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


Tat protein of HIV-1 is a potent transactivator of transcription and essential for HIV-1 replication. In addition, Tat has been proposed to possess immunosuppressive functions, suggesting that Tat may play a direct role in the immune dysfunction associated with AIDS. Recently, it has been reported that Tat represses activity of a major histocompatibility complex (MHC) class I gene promoter. Because HIV infection downmodulates expression of class I molecules, this data strongly suggests that Tat downregulates class I expression and leads to loss of CTL activity. Here, we report effects of Tat on class I expression using a human cell line, T0, expressing Tat (T0- Tat). Northern blot analysis shows that levels of MHC class I transcripts are normal in T0-Tat. Flow cytometry analyses indicate that expression of HLA class I molecules is not substantially downregulated to any great extent by Tat in T0-Tat. Further, pulse-chase experiments followed by Endoglycosidase- H treatment show that the rate of maturation and processing of class I molecules in T0-Tat is indistinguishable from that in the original cell line, T0. Taken together, these data suggest that Tat expression does not necessarily result in downregulation of class I expression.

Original languageEnglish (US)
Pages (from-to)233-240
Number of pages8
JournalJournal of Acquired Immune Deficiency Syndromes and Human Retrovirology
Issue number3
StatePublished - 1996


  • HIV-1
  • Immunosuppression
  • MHC class I molecule
  • Tat

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology
  • Virology


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