Abstract
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 language | English (US) |
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Pages (from-to) | 233-240 |
Number of pages | 8 |
Journal | Journal of Acquired Immune Deficiency Syndromes and Human Retrovirology |
Volume | 11 |
Issue number | 3 |
DOIs | |
State | Published - 1996 |
Externally published | Yes |
Keywords
- HIV-1
- Immunosuppression
- MHC class I molecule
- Tat
ASJC Scopus subject areas
- Immunology and Allergy
- Immunology
- Virology