Inhibition of HIV replication by immunoliposomal antisense oligonucleotide.

The sequence-specific suppression of HIV-1 replication using CD4 monoclonal-antibody-targeted liposomes, containing Rev antisense phosphorothioate oligonucleotides is described. Liposomes were prepared by encapsulating the 20-mer antisense DNA sequence of the rev HIV-1 regulatory gene, in the form of a phosphorothioate oligonucleotide. Specific targeting was accomplished by conjugating anti-CD4 mouse monoclonal antibody to the surface of the liposomes. HIV-1-infected H9 cells as well as peripheral blood T-lymphocytes were incubated with the immunoliposomes of antisense found to have potential antiviral effect. HIV-1 replication was reduced by 85% in antisense immunoliposome-treated H9 cells and peripheral blood lymphocytes, whereas the inhibition of HIV-1 replication was not observed using either empty immunoliposomes or immunoliposomes containing scrambled Rev phosphorothioate oligonucleotide sequences. The antiviral activity of both the free and the encapsulated oligonucleotides were assessed by p24, reverse transcriptase (RT) assays and polymerase chain reaction (PCR) analysis. Liposome preparations demonstrated minimal toxicity in H9 as well as in peripheral blood lymphocyte cell culture experiments. These in vitro culture results demonstrate the potential efficacy of immunoliposomes to inhibit HIV replication.

Inhibition of HIV-1 replication in H9 cells by nystatin-A compared with other antiviral agents.

Nystatin A was compared in vitro with amphotericin B, AZT, or foscarnet for their respective abilities to inhibit the replication of human immunodeficiency virus type 1 (HIV-1) in H9 cells. HIV-1-infected H9 cells were cultured for 7 days in the presence of each of these drugs, at various concentrations. Reverse transcriptase activity and p24 antigen production were quantitated. Untreated, HIV-1-infected H9 cells served as the control. Nystatin A inhibited viral replication most effectively at 10 micrograms/ml, a concentration that did not affect cell viability. Nystatin-A treatment inhibited RT activity by 85% and p24 production by 90%. These levels of inhibition were comparable to that mediated by amphotericin B, AZT, or foscarnet at 10, 25, and 50 micrograms/ml, respectively. Western blot analysis of the HIV-1-infected H9 cells treated with these drugs did not detect any expression of viral proteins. These findings were further corroborated by indirect immunofluorescence studies using monoclonal anti-gp120 FITC-conjugated antibodies and by polymerase chain reaction for proviral DNA analysis, using a 32P-labeled probe. These results suggest that Nystatin A merits attention as an antiviral drug for the treatment of HIV-1 infection. In vivo drug delivery by liposome encapsulation to overcome problems of bioavailability is currently under study.

Impaired cytokine response in male ICR Swiss mice after infection with D variant of encephalomyocarditis virus.

The basis for the resistance of the female and the susceptibility of the male ICR Swiss mouse to the diabetogenicity of the D variant of encephalomyocarditis virus (EMCV-D) is unknown. This pattern of disease resistance and susceptibility can be reversed if females are treated with testosterone and males are treated with estrogen before virus infection. As a possible explanation for this sex difference in disease development, differences in early antiviral host responses were explored. Cellular antiviral resistance mechanisms operative early in virus infection were evaluated in ICR Swiss mice of both sexes after intraperitoneal infection with virus. No differences were seen in splenic natural killer (NK) cell responses of male and female mice during the 1st wk of infection, during which only the males became diabetic. Depletion of NK cell activity with rabbit anti-asialo GM1 serum did not render the infected ICR Swiss female susceptible to virus-induced diabetes. Treatment of ICR Swiss mice with type I carrageenan to compromise macrophage function rendered the female susceptible to diabetes after infection with EMCV-D but made only the male susceptible to diabetes by the usually avirulent interferon-inducing EMCV-D. Concanavalin A and recombinant interleukin 2, inducers of immune interferon, which in turn primes macrophages for activation and induces their expression of la antigens, protected the ICR Swiss male against the diabetogenic effects of EMCV-D. Interleukin 2 enhanced the male's capacity to exhibit an increase in the expression of Ia antigen by peritoneal exudate cells 1 day after injection with EMCU-D to a level seen in disease-resistant females.(ABSTRACT TRUNCATED AT 250 WORDS)

A murine model of insulin-dependent diabetes mellitus resulting from the cumulative effects of the nondiabetogenic strain of encephalomyocarditis virus and a single low dose of streptozocin.

The induction of insulin-dependent diabetes in outbred male and female mice was examined using a combination of the usually nondiabetogenic B-variant of encephalomyocarditis (EMC-B) virus and single low doses of streptozocin (STZ). Neither EMC-B virus nor low doses of STZ were overtly diabetogenic when administered alone; however, when these two insults occurred 1 day apart, diabetes resulted in male but not in female mice. The induction of diabetes was dependent on the time interval between these two insults, since EMC-B virus and STZ given 4 days apart did not induce diabetes. Unexpectedly, when the order of these two insults was reversed, diabetes occurred. The absence of diabetes when EMC-B virus was given before STZ suggested the possibility that virus-induced interferon blocked the cytotoxic effects of STZ. This suggestion was supported by the observation that an antiserum against beta interferon abrogated the virus-mediated protection against STZ-mediated cytotoxicity. Also, Poly I:C administered before a single diabetogenic dose of STZ delayed the onset of severe hyperglycemia.