Table 2.

In vitro type I IFN action against HIV/SIV infection.

Type I IFN	Cells	Main Results	Ref.
IFNα	Peripheral blood mononuclear cells	IFN has a dose-related suppressive effect on HTLV-III replication	54
IFNα1, IFNα2 IFNβ, IFN leukocyte	Peripheral blood mononuclear cells	IFN preparations suppress LAV, HTLV-III, and ARV-2 replication as measured by reverse transcriptase (RT) activity by greater than 50%. This suppression was dose dependent and high dosages (500 Units/ml) of IFNα resulted in almost complete suppression of RT activities (77–99%)	55
IFNα, IFNβ	Peripheral blood mononuclear cells, H9 lymphocytic and monocytoid U937 cell lines	IFNs show similar concentration-dependent antiHIV activity. No reduction in HIV expression are observed when persistently infected H9 cells are treated with high dose of IFN	56
IFNα2	Stable cell lines, derived from Vero cells and A3.01 cells, that express IFN gene	The transcription and replication of HIV was completely inhibited by IFN	57
IFNα	HIV infected H9 lymphocytic cells	HIV-1 replication is inhibited by a maximum of 22% at 1000 Units/ml of IFN	58
IFNβ	Peripheral blood mononuclear cells	IFN reduces replication of HIV. The effect is most pronounced when high levels of the IFN are employed	59
IFNα	Promonocytic (U1) and T lymphocytic (ACH-2) cell lines chronically infected with HIV	IFN inhibits the release of RT, viral antigens, the production or release (or both) of whole HIV virions, but has no effect on the amount of cell-associated viral proteins	60
IFNα, IFNβ	Chronically HIV infected monocytoid U937 cells	The addition of 1000 Units of IFN per ml to HIV-infected U937 cells resulted in some inhibition of virus production	61
IFNα, IFNβ	Monocyte-derived macrophage	IFN acts to restrict the formation of proviral DNA	62
IFNα, IFNβ	T cells or monocytes	Levels of RT activity in IFN-treated HIV-infected T cells are half those in control cultures, but the frequency of infected cells or the levels of p24 released in culture fluids are unchanged	63
		Monocytes treated with IFNs at the time of virus challenge showed no evidence of HIV infection: no p24 antigen or RT activity, no viral mRNA, and no proviral DNA. Monocytes treated with IFN 7 days after HIV infection are not free of the retroviral pathogen
IFNα	Chronically HIV infected Tlymphocytic ACH-2 and promonocytic Ul cell lines	IFN, although effective in suppressing the release of HIV particles, do not inhibit shedding of p24, gag into the culture supernatants	64
IFNα, IFNβ	HeLa T4 cells	IFNs inhibit syncytium formation induced by HIV-1 envelope glycoprotein and are found to be potent inhibitors of HIV-1 induced cell fusion	65
IFNα	T-cell, H9, CEM, C3, and Jurkat cell lines	IFN decreases virus production (extracellular RT and p24 antigen levels in the supernatant medium). Chronically infected Jurkat cells treated with IFN appear to be inhibited in growth rate, as virus production decreased with cell number	66
IFNα	CEM-174	Pretreatment of cells with 50 to 500 Units of IFN per ml result in a marked reduction in HIV RNA and protein synthesis. IFN-induced inhibition of viral protein synthesis is detected only when cells were treated with IFNα prior to infection or when IFNα are added up to 10 h postinfection, but not if IFNα are added at the later stages of HIV-1 replication cycle or after the HIV-1 infection is already established	67
IFNα	Peripheral blood mononuclear cell	A marked depletion of envelope glycoprotein (gp120) in HIV virions released from IFN-treated cells	68
IFNα, IFNβ	Monocytes derived macrophage	Macrophages pretreated with IFNs have a reduced HIV DNA signal while the spliced mRNA signal is essentially abolished. No virus is produced. The addition of IFNs does not affect the levels of HIV spliced transcripts in cells with established productive infection	69
IFNα, IFNβ	Chronically HIV infected monocytoid U937 cells and CEM cells	IFN treatment induces a specific block on HIV mRNA translation	70
IFNα, IFNβ	MT4 cells	IFNs block an early step in SIV replication while HIV gene expression was disrupted at a later point. Both the stability and proteolytic processing of HIV specific proteins were altered in IFN-treated cells	71
IFNα	Monocytes derived macrophage	IFN affect early steps of HIV-1 BaL replication, preceding the completion of viral DNA synthesis	72
IFNα	Chronically HIV infected monocytoid U937 cells	IFN affects late stages of HIV-1 replication, by inhibiting virus assembly and release, and by reducing the infectivity of shed virions	73
IFNα1b, IFNα2a, IFNα2b, IFNβ1a	T-cell lines (MT4R5, Jurkat, HUT-78, CEM) and primary CD4 T lymphocytes	IFNs have a limited effect on HIV spread, measured as the appearance of Gag-expressing cells	74
		Cell-to-cell HIV transfer is less sensitive to IFN than infection by cell-free virions
IFNε	FRT epithelial cancer cell line and Sup-T1 lymphoma line	IFN impairs HIV infection at stages post HIV entry and up to the translation of viral proteins	75