Relief of preintegration inhibition and characterization of additional blocks for HIV replication in primary mouse T cells.
Development of a small animal model to study HIV replication and pathogenesis has been hampered by the failure of the virus to replicate in non-primate cells. Most studies aimed at achieving replication in murine cells have been limited to fibroblast cell lines, but generating an appropriate model requires overcoming blocks to viral replication in primary T cells. We have studied HIV-1 replication in CD4(+) T cells from human CD4/CCR5/Cyclin T1 transgenic mice. Expression of hCD4 and hCCR5 in mouse CD4(+) T cells enabled efficient entry of R5 strain HIV-1. In mouse T cells, HIV-1 underwent reverse transcription and nuclear import as efficiently as in human T cells. In contrast, chromosomal integration of HIV-1 proviral DNA was inefficient in activated mouse T cells. This process was greatly enhanced by providing a secondary T cell receptor (TCR) signal after HIV-1 infection, especially between 12 to 24 h post infection. This effect was specific for primary mouse T cells. The pathways involved in HIV replication appear to be PKCtheta-, CARMA1-, and WASp-independent. Treatment with Cyclosporin A (CsA) further relieved the pre-integration block. However, transcription of HIV-1 RNA was still reduced in mouse CD4(+) T cells despite expression of the hCyclin T1 transgene. Additional post-transcriptional defects were observed at the levels of Gag expression, Gag processing, Gag release and virus infectivity. Together, these post-integration defects resulted in a dramatically reduced yield of infectious virus (300-500 fold) after a single cycle of HIV-1 replication. This study implies the existence of host factors, in addition to those already identified, that are critical for HIV-1 replication in mouse cells. This study also highlights the differences between primary T cells and cell lines regarding pre-integration steps in the HIV-1 replication cycle.
Zhang
Jing-xin
JX
The Kimmel Center for Biology and Medicine of the Skirball Institute, New York University School of Medicine, New York, New York, United States of America.
Diehl
Gretchen E
GE
Littman
Dan R
DR
D021581:Active Transport, Cell Nucleus / Q000187:drug effects; D000818:Animals; D015704:CD4 Antigens / Q000378:metabolism; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism / Q000821:virology; D002478:Cells, Cultured; D056906:Cyclin T; D016213:Cyclins / Q000378:metabolism; D016572:Cyclosporine / Q000494:pharmacology; D015658:HIV Infections / Q000821:virology; D016325:HIV Long Terminal Repeat; D015497:HIV-1 / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology*; D006801:Humans; D051379:Mice; D008822:Mice, Transgenic; D014176:Protein Biosynthesis / Q000187:drug effects; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism; D019713:Receptors, CCR5 / Q000378:metabolism; D048348:Reverse Transcription / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects; D013045:Species Specificity; D013601:T-Lymphocytes / Q000187:drug effects / Q000821:virology*; D016662:Virus Integration / Q000187:drug effects; D053586:Virus Internalization / Q000187:drug effects; D014779:Virus Replication / Q000187:drug effects
C503684:CCNT1 protein, human; D015704:CD4 Antigens; D056906:Cyclin T; D016213:Cyclins; D011948:Receptors, Antigen, T-Cell; D019713:Receptors, CCR5; D016572:Cyclosporine