Immunoprophylactic strategies against respiratory influenza virus infection.

The objective of this report is to evaluate the prophylactic efficacy of liposome-mediated immunotherapy for prevention of respiratory influenza virus infection in mice. Antiviral antibody, interferon-gamma and poly (ICLC) were encapsulated in liposomes and they were evaluated for their ability to induce protective immunity against lethal influenza infection. Passive immunization using liposome-encapsulated antiviral antibody was found to offer complete protection against the virus challenge. However, this pretreatment must be administered within 24 h prior to virus challenge to be protective. Pretreatment with liposome-encapsulated interferon-gamma was found to stimulate cellular immune responses, but the protection is partial. Immunoprophylaxis using liposome-encapsulated double-stranded (ds) RNA poly (ICLC) provided complete and longer-lasting protection against influenza infection. These results suggest liposome-mediated immunoprophylactic approaches are effective in the prevention of respiratory influenza virus infection.

Immunochemotherapy for Leishmania donovani infection in golden hamsters: combinatorial action of poly ICLC plus L-arginine and sodium stibogluconate (Stibanate).

We demonstrate that golden hamsters infected with Leishmania donovani amastigotes develop the capacity to eliminate intracellular pathogens on treatment with low-dose standard antileishmanial sodium stibogluconate (Stibanate) in combination with polyinosinic-polycytidilic acid stabilized with polylysine and carboxymethycellulose (poly ICLC), a potent inducer of interferon (IFN) and immune enhancer, plus L-arginine. Data suggest that low doses of both Stibanate and poly ICLC plus L-arginine provide marginal inhibition against L. donovani infection in golden hamsters. When given in combination, however, a significant inhibition was achieved without toxicity, as all the animals survived up to 45 or 60 days. These results suggest that combination therapy using Stibanate and poly ICLC plus L-arginine may be very effective in reducing the dose of Stibanate and, hence, its dose-dependent toxicity in clinical situations.

Poly ICLC enhances the antimalarial activity of chloroquine against multidrug-resistant Plasmodium yoelii nigeriensis in mice.

Swiss mice infected with multidrug-resistant Plasmodium yoelii nigeriensis were treated with polyinosinic-polycytidylic acid stabilized with polylysine and carboxymethyl cellulose (Poly ICLC), a potent interferon (IFN) inducer and immune enhancer, in combination with chloroquine (CQ), which completely eliminated the malaria parasite from these animals. The enhancement of the antimalarial activity of poly ICLC was found to be completely reversed by the cytochrome P-450 inducer, phenobarbitone. No effect of Nw nitro-L-arginine (NLA), an inhibitor of nitric oxide, was seen on the enhancement of the antimalarial activity of CQ by Poly ICLC. These results suggest the possible involvement of cytochrome P-450 enzyme-mediated mechanism in the enhancement of the antimalarial activity of CQ by Poly ICLC.

Long-term treatment of malignant gliomas with intramuscularly administered polyinosinic-polycytidylic acid stabilized with polylysine and carboxymethylcellulose: an open pilot study.

Polyinosinic-polycytidylic acid stabilized with polylysine and carboxymethylcellulose (poly-ICLC) (10-50 mcg/kg, administered intramuscularly one to three times weekly) was given for < or = 56 months to 38 patients with malignant gliomas. There was minimal or no toxicity. Twenty of 30 patients (66%) receiving at least twice weekly poly-ICLC showed regression or stabilization of gadolinium-enhancing tumor, as revealed by magnetic resonance imaging (median = 65% volume decrease). All but one patient with anaplastic astrocytomas who received continuous poly-ICLC remain alive, with a median progression-free survival of 54 months from diagnosis. Median Kaplan-Meier survival is 19 months for patients with glioblastomas who receive at least twice weekly poly-ICLC treatments. Tumor response was associated with 2',5' -oligoadenylate synthetase activation (P = 0.03) but not with serum interferon. We hypothesize clinical activation by poly-ICLC of a basic host tumor suppressor system. Prolonged, quality survival with tumor stabilization or regression confirmed by magnetic resonance imaging for most patients with anaplastic astrocytomas and glioblastomas suggests that more extensive laboratory and controlled clinical studies are warranted. The concept of long-term, broad spectrum stimulation of host defenses with nontoxic, inexpensive double-stranded ribonucleic acids, such as low-dose poly-ICLC, may be applicable to the treatment of other malignancies.

Killing of Leishmania donovani amastigotes by poly ICLC in hamsters.

In vitro as well as in vivo studies suggest that cytokine-induced synthesis of nitric oxide (NO) from L-arginine is a major effector mechanism against intracellular pathogens. In this study, we demonstrate that golden hamsters infected with Leishmania donovani amastigotes upon treatment with polyinosinic-polycytidylic acid stabilized with polylysine and carboxymethylcellulose (poly ICLC), a potent interferon inducer and immune enhancer, in combination with L-arginine, develop the capacity to eliminate intracellular pathogens. This antileishmanial activity of poly ICLC was suppressed by N w nitro-L-arginine (N w NLA), an inhibitor of inducible NO synthase. Furthermore, prolonged treatment of infected animals with L-arginine alone for 5 days more after 5 day treatment with poly ICLC plus L-arginine increased the antileishmanial activity compared with 5 day treatment with poly ICLC plus L-arginine, suggesting that inducible NO synthase, once activated, produces NO for 5 days more. Our results suggest that an L-arginine-dependent, NO-mediated mechanism is probably responsible for the antileishmanial action of poly ICLC.

Poly ICLC inhibits Plasmodium cynomolgi B malaria infection in rhesus monkeys.

Prophylatic treatment with a single dose of 1.0 or 2.0 mg/kg (body weight) of polyinosinic-polycytidylic acid stabilized with polylysine and carboxymethylcellulose (Poly ICLC), a potent interferon (IFN) inducer and immune enhancer, 18 h before intravenous inoculation of sporozoites (1.04 x 10(5)-0.70 x 10(6) sporozoites) of Plasmodium cynomolgi B in the rhesus monkey, completely abolished the infectivity of sporozoites. The inhibitory effect of Poly ICLC is dose dependent in monkeys infected with P. cynomolgi B sporozoites. Treatment with lower doses of Poly ICLC (0.5 mg/kg) provided significant protection, but the lowest dose of Poly ICLC used (0.1 mg/kg) failed to provide any protection. Prophylactic treatment with Poly ICLC, however, had no protective effect against trophozoite-induced infection.

Reabuse rates in a sample of children followed for 5 years after discharge from a child abuse inpatient assessment program.

Efforts to accurately measure rates of reabuse have been elusive because of problems in definition and methodology. The present study examines reabuse rates across a 5-year follow-up period in a sample of children assessed for child abuse (October 1986-October 1987). Participants consisted of 304 children (7 months-15 years of age), systematically selected from a population of 1,100 children consecutively admitted to a hospital-based, interdisciplinary, child abuse assessment unit. Reabuse was determined by matching sample names against information in a centralized reporting system. Reabuse was studied across demographic and socioeconomic variables, vulnerability days, initial and subsequent type(s) of abuse, and other considerations. At the end of the 61-72 month follow-up period, the sample had a 16.8% incidence of reabuse. The greatest risk of reabuse occurred during the first 2 years following an initial discharge diagnosis of maltreatment. Although no particular initial maltreatment diagnosis was a statistically significant predictor of the likelihood or type of reabuse, neglect was shown to be the most frequent type of reabuse. Children experiencing reabuse were more likely to reside in public housing/apartments, have unmarried and/or unemployed parent(s), and be Medicaid recipients. Opportunities for secondary prevention initiatives and future research are discussed.

Prophylactic and therapeutic efficacies of poly(IC.LC) against respiratory influenza A virus infection in mice.

Polyriboinosinic-polyribocytidylic acid [poly(IC.LC)] was evaluated for its prophylactic and therapeutic efficacies against respiratory influenza A virus infection in mice. Two doses of poly(IC.LC) (1 mg/kg of body weight per dose) administered intranasally within 12 days prior to infection with 10 50% lethal doses of mouse-adapted influenza A/PR/8 virus fully protected the mice against the infection. Determination of virus titers by hemagglutination and plaque assays showed more than a 2-log10 decrease in virus titers in lung homogenates of pretreated mice compared with those in the lungs of the nonpretreated group. Treatment of infected mice with poly(IC.LC) resulted in a modest (40%) survival rate. These results suggest that poly(IC.LC) provides a highly effective prophylaxis against respiratory influenza A virus infection in mice.

Treatment of intracranial alphavirus infections in mice by a combination of specific antibodies and an interferon inducer.

Finding an effective treatment for viral infections that cause encephalitis remains an important problem. A model of human alphavirus infections, Semliki Forest virus, causes lethal encephalitis in weanling mice. Mice are viremic within 24 hr of an intraperitoneal challenge with the equivalent of three 75% lethal doses of Semliki Forest virus. Virus reaches the brain by 48 hr, and mortality results in all mice in 5-7 days. Introduction of virus intracranially accelerates the course of the infection. Neither anti-Semliki Forest virus hyperimmune serum nor the potent interferon inducer poly I:CLC given intraperitoneally are protective when used therapeutically after an intracranial virus infection, but a combination of 1,000 U hyperimmune serum and 80 micrograms/mouse of poly I:CLC results in a 50% survival rate. This combination treatment of intracranial Semliki Forest virus infection eliminates detectable viremia and reduces virus load in the brain over the course of the infection. These data show that when combined, specific antibody and an interferon inducer can interact synergistically to protect mice from alphavirus infections of the central nervous system even when given after the virus is replicating in the target organ.

A practical approach to children failing in school.

The most likely causes of failure in school in otherwise capable children who come from homes in which they are loved and cared for are learning disabilities, affective illness, primary disorder of vigilance and, on occasion, narcolepsy. The various learning disabilities are often accompanied by problems of attention, concentration, organization, mood and feelings, and social interaction. These latter problems are reflections of biochemical disorders that respond effectively to judicious pharmacologic intervention. When this type of medical management is combined with constructive counseling and suitable curriculum adjustments, the child can attain his or her maximum education potential and become a productive and contributing adult member of society.

A comparison of interferon responses to poly ICLC in males and females.

Interferon (IFN) responses to polyriboinosinic acid polyribocytidylic acid in poly-L-lysine and carboxymethylcellulose (poly ICLC) have been studied in detail in 6 men and 3 women as part of a preliminary trial in patients with multiple sclerosis (MS). Patients received intravenous (i.v.) doses of 100 micrograms/kg poly ICLC, and serum IFN levels were determined serially every 4 h for 16 h. Men and women produced substantial levels of IFN at 8, 12, and 16 h after infusion, but levels in men were consistently and significantly higher (p less than 0.05). Interferon responses were examined also in 3 male and 3 female Rhesus monkeys. Serum samples were obtained 8 and 24 h after i.v. injections of 1 mg/kg of poly ICLC. Again, there were significantly higher levels of IFN in males. The observed differences may reflect sex-linked differences in either drug metabolism or specific sensitivity to IFN induction by poly ICLC. The most interesting possibility is that the difference is due to a more general difference in IFN response between males and females. Studies are currently in progress to evaluate these possibilities.

Gamma-interferon induction in patients with chronic progressive MS.

Although gamma interferon (gamma-IFN) may be involved in the pathogenesis of exacerbations of multiple sclerosis (MS), whether it plays a role in chronic progressive MS is not known. To investigate this, we retrospectively analyzed serum samples from nine chronic progressive MS patients who were treated with monthly intravenous infusions of the interferon inducer polyinosinic acid polycytidylic acid polylysine in carboxymethylcellulose (poly ICLC). Using a bioassay we found that the mean peak total interferon level was 177 U/ml 12 hours after infusion, and using a radioimmunoassay we found that the mean peak gamma-IFN level was 15.9 U/ml 12 hours after infusion, so that gamma-IFN made up approximately 10% of the total. Greater gamma-IFN induction did not correlate with clinical worsening; induced gamma-IFN levels were not higher in two patients who worsened on treatment, and the highest levels were found in a patient who remained stable. Either chronic progressive MS is not sensitive to gamma-IFN or the effects of gamma-IFN are masked by other mediators induced by poly ICLC.

Changes in leukocyte recirculation, NK cell activity, and HLA-DR expression in peripheral blood mononuclear cells of MS patients treated with Poly ICLC.

To investigate the cellular immune effects of the interferon inducer, Poly ICLC, in humans, peripheral blood mononuclear cells from patients with multiple sclerosis receiving Poly ICLC as part of a preliminary clinical trial were studied. Peripheral blood mononuclear cell phenotype analysis using fluoresceinated monoclonal antibodies and flow microfluorometry showed decreases in the percentages and absolute numbers of all lymphocyte subsets 24 h after infusion. These changes returned toward baseline at 48 h except the percentage of CD-4 positive cell which increased above baseline levels. The percentage of HLA-DR antigen positive cells and CD-16 (Leu 11a) positive cells were increased 24 h after infusion but returned to baseline at 48 h. NK activity as determined by chromium release from K562 target cells was decreased at 24 h but increased 48 h after drug infusion. The increases in percentages of HLA-DR antigen and CD-16 positive cells at 24 h and NK activity at 48 h are consistent with the in vitro effects of IFN while the decreases in peripheral blood mononuclear cells are suggestive of changes in cell recirculation.

Postinfection therapy of arbovirus infections in mice.

Most antiviral agents are efficacious prophylactically in vivo, and a few are efficacious for postinfection (p.i.) therapy. To explore possibilities for p.i. therapy of encephalogenic Banzi virus (BZV) and Semliki Forest virus infections in mice, we evaluated candidate antiviral therapies after development of the first clinical signs of infection. The earliest clinical indication of BZV viremia in mice is a rise in core body temperature beginning on day 3 p.i. BZV-infected mice showing elevated core body temperatures (greater than or equal to 37.3 degrees C) on days 3 and 4 p.i. were treated intraperitoneally with the interferon inducer poly(ICLC) (80 micrograms per mouse) and/or specific antiserum. Combined therapy on day 3 of a BZV infection protected over 75% of mice showing clinical evidence of viral disease before treatment. Protection against early brain infection must occur on day 4 p.i., since by that day BZV has started multiplying in the brains of the mice. Significant protection occurred with antiserum alone and increased with poly(ICLC). Similar protection was obtained during Semliki Forest virus viremia, but this infection is so rapid that the first clinical signs are reliably detectable only after viremia.

The kinetics of interferon induction by poly ICLC in humans.

A preliminary trial of the interferon (IFN) inducer polyriboinosinic acid-polyribocytidylic acid in poly-L-lysine and carboxymethylcellulose (poly ICLC) was conducted in patients with chronic progressive multiple sclerosis (MS). Because IFN induction in men is greater than in women, the kinetics of IFN induction were studied. As no significant differences were found in the serum half-life of IFN, sex-linked differences in IFN clearance or degradation are not likely to be responsible for the differences noted. Because fever was the major limiting side effect in MS patient, the relationship of fever to IFN levels was assessed. Changes in temperature were not related to changes in IFN levels, suggesting that fever might be blocked without reducing IFN levels.

Cortisol induction by poly ICLC: implications for clinical trials of interferon.

Because interferon injections have recently been reported to induce cortisol in cancer patients, we retrospectively reviewed cortisol levels obtained during a preliminary trial of the interferon inducer polyriboinosinic polyribocytidylic acid in poly-L-lysine and carboxymethylcellulose (poly ICLC) in multiple sclerosis patients to determine if significant cortisol induction occurred. Analysis of data from 51 poly ICLC infusions in 6 men and 4 women showed elevated cortisol levels 4 to 16 hours after infusion, with hematological changes consistent with steroid effect. The highest cortisol levels observed were in 2 patients who improved during the treatment period, but there was no clear relationship between cortisol levels and clinical outcome in the group as a whole.

Ranking of prophylactic efficacy of poly(ICLC) against Rift Valley fever virus infection in mice by incremental relative risk of death.

The prophylactic efficacy of poly(ICLC) (stabilized, synthetic, double-stranded polyriboinosinic-polyribocytidylic acid) against Rift Valley fever virus infection in Swiss-Webster mice was dependent on the treatment schedule. The treatment schedule was optimized by ranking the results of various treatments by the Cox proportional-hazard model based on the incremental relative risk of death. With this ranking procedure, the schedule of choice was three doses of 20 micrograms each given 5 days apart. This regimen yielded a 90% survival rate. Additional parameters were determined, including the timing of the first and second drug dose, the temporal relationship of these treatments to the day of challenge, and the minimal effective dose (1 microgram per mouse).

Enhanced therapeutic efficacy of poly(ICLC) and ribavirin combinations against Rift Valley fever virus infection in mice.

The therapeutic efficacy of polyriboinosinic-polyribocytidylic acid stabilized with poly-L-lysine and carboxymethyl cellulose [poly(ICLC)] given alone or in combination with ribavirin was evaluated in Swiss Webster mice infected with Rift Valley fever virus. Four or more 20-micrograms doses of poly(ICLC) given at various intervals beginning 24 h after infection protected all mice against death. On the other hand, a treatment regimen consisting of only three doses of poly(ICLC) given 24 h postinfection resulted in a 50% survival rate. When initiated 48 h postinfection, an extended treatment regimen with the same dose was required to yield 40% survivors. Lower doses (5 micrograms) of poly(ICLC) per mouse were only marginally effective even when six injections were given between days 1 and 9 postinfection. The combined administration of ribavirin and poly(ICLC) initiated as late as 48 h postinfection was effective even when treatment consisted of doses that were ineffective when either drug was used alone.