Ronald B. Moss

Phase 1 clinical trials of the safety and immunogenicity of adjuvanted plasmid DNA vaccines encoding influenza A virus H5 hemagglutinin.

BACKGROUND Development of vaccines against highly pathogenic avian influenza virus H5N1 subtypes posing a pandemic threat remains a priority. Limitations in manufacturing capacity and production time of conventional inactivated vaccines highlight the need for additional approaches. METHODS We conducted two double-blind, placebo-controlled phase 1 studies involving a total of 103 healthy adults who received two intramuscular injections of Vaxfectin-adjuvanted plasmid DNA vaccine or placebo 21 days apart. Vaccine cohorts received either a monovalent vaccine containing an A/Vietnam/1203/04 H5 hemagglutinin-encoding plasmid or a trivalent vaccine with plasmids encoding H5, NP, and M2 proteins in doses from 0.1 to 1mg of DNA/injection. RESULTS All doses were well tolerated without vaccine-related serious adverse events or discontinuations. In the monovalent cohorts, hemagglutination inhibition (HI) titers of > or =40 and 4-fold rises from baseline were achieved in 47-67% of subjects and H5-specific T-cell responses in 75-100%. Trivalent cohorts had lower HI response rates (< or = 20%), but 72% of subjects achieved T-cell and/or antibody responses to one or more antigens. CONCLUSIONS Vaxfectin-adjuvanted monovalent H5 DNA vaccines were well tolerated and induced HI response rates and titers in the reported range of inactivated protein-based H5 vaccines, suggesting that adjuvanted DNA vaccines with rapid vaccine production could be useful for pandemic control.

TNF-α and Chronic Fatigue Syndrome

Based upon the clinical presentation of chronic fatigue syndrome (CFS), we hypothesized that proinflammatory cytokines may play a role in the pathogenesis of the disease. We therefore undertook a retrospective cross-sectional study to examine the role of TNF-α in patients with CFS. Our results suggest a significant increase serum TNF-α in patients with CFS (P < 0.0001) compared to non-CFS controls. This study supports the further examination of the role of proinflammatory mediators in CFS. Furthermore, the clinical testing of TNF-α blockers and other antiinflammatory agents for the treatment of this disease is warranted.

CD4+CD8dim T lymphocytes exhibit enhanced cytokine expression, proliferation and cytotoxic activity in response to HCMV and HIV‐1 antigens

CD4+CD8dim T cells represent a minor subset of the total CD3+ T cell population in peripheral blood. Although transient and persistent expansions of these cells havebeen reported in both healthy and diseased individuals, the functional properties of the CD4+CD8dim population are largely unknown. In this study, we examined antigen‐specific cytokine and proliferative responses of the CD4+CD8dim subset. In whole blood cultures stimulated with the viral antigens HCMV and HIV‐1, a significant fraction of the CD4+CD8dim subset exhibited cytokine expression and proliferation in response to antigen activation. Typically, the CD4+CD8dim population contained two‐ to eightfold higher frequencies of antigen‐specific cytokine producing cells than the CD4+CD8‐ population. Phenotypic analysis of the cytokine expressing CD4+CD8dim population indicated that these cells are memory T cells, with a high frequency of this population expressing the cytotoxic markers CD56 and perforin. Furthermore, the CD4+CD8dim cytokine responses to CMV were shown to be MHC class II dependent. Significantly, purified CD4+CD8dim T cells were found to possess higher CMV‐specific cytotoxic activity than purified CD4+CD8– T cells in a standard 51Cr‐release CTL assay. Thus, CD4+CD8dim T cells appear to be MHC class II dependent, are capable of cytolytic effector activity, and are highly enriched within the CD4+ cell populations specific for HCMV and HIV‐1.

Th1/Th2 cells in inflammatory disease states: therapeutic implications

Inflammation is initiated as a protective response by the host, but can often result in systemic pathology. Among cells of the immune system, T lympho-cytes play a major role in the inflammatory response. T cell inflammation is characterised histologically by an infiltration of mononuclear cells. Key regulators of this response are a subset of T lymphocytes called T helper (Th) cells. These cells secrete soluble mediators called cytokines, which orchestrate the immune response. The appropriate regulation of Th cell immunity is critical in the control and prevention of diverse disease states. This review will focus on the role of Th cells in the inflammatory process involved in allergic disease, diabetes, infectious disease, rheumatoid arthritis, heart disease, multiple sclerosis and cancer. In the area of autoimmunity, in particular, a basic understanding of Th cells and cytokines has contributed to the development of clinically efficacious biological agents. This review also examines current and novel treatment strategies under investigation at present that regulate Th cell immunity, which may result in better treatments for immune-mediated diseases.

A Phase II study of DAS181, a novel host directed antiviral for the treatment of influenza infection

BACKGROUND DAS181, a novel host-directed antiviral in development for influenza treatment, was assessed in this phase II clinical trial. METHODS This study was a double-blind, placebo-controlled phase II clinical trial assessing influenza viral load and patient safety in otherwise healthy influenza-infected participants. Participants were randomized to a single-dose, multiple-dose, or placebo group and were followed for safety and virologic outcomes. RESULTS A total of 177 laboratory-confirmed influenza-infected participants were enrolled in the trial, which encompassed 3 influenza seasons from 2009-2011 in both the Northern and Southern Hemispheres. Thirty-seven percent of participants had confirmed infection with influenza B, 33% with seasonal H3N2, 29% with pandemic 2009 H1N1, and 1 participant was positive for both influenza B and pandemic 2009 H1N1. Significant effects were observed in regard to decreased change from baseline viral load and viral shedding in the multiple-dose group compared with placebo as measured by quantitative polymerase chain reaction (P < .05). No instances of H274Y were observed among viral isolates from this trial. Overall, the drug was generally well tolerated. CONCLUSIONS DAS181 significantly reduced viral load in participants infected with influenza, thus warranting future clinical development of this novel host-directed therapy. CLINICAL TRIALS.GOV IDENTIFIER: NCT01037205.

Mucosal Immunization with Inactivated Human Immunodeficiency Virus plus CpG Oligodeoxynucleotides Induces Genital Immune Responses and Protection against Intravaginal Challenge

Vaccines capable of protecting against sexually transmitted infections, such as human immunodeficiency virus (HIV), will depend on the induction of potent long-lasting mucosal immune responses in the genital tract. We evaluated vaginal and systemic immune responses and protection from vaginal challenge elicited after intranasal immunization of mice with inactivated glycoprotien 120-depleted HIV-1 immunogen alone or in combination with immunostimulatory CpG oligodeoxynucleotides (ODNs). Mice immunized with HIV-1 immunogen plus CpG ODN had significantly enhanced levels of anti-protein 24 immunoglobulin (Ig) G and IgA antibodies in serum and vaginal washes and increased production of beta-chemokines and interferon-gamma, compared with mice immunized with HIV-1 immunogen alone or with control ODN. Furthermore, mice intranasally immunized with HIV-1 immunogen plus CpG were protected against intravaginal challenge with a recombinant vaccinia virus expressing HIV-1 gag. These results indicate that mucosal immunization with whole-killed HIV-1 plus CpG ODN may be an effective means of inducing local immunity and protection against genital infection.

Inhibition of neuraminidase inhibitor-resistant influenza virus by DAS181, a novel sialidase fusion protein.

Antiviral drug resistance for influenza therapies remains a concern due to the high prevalence of H1N1 2009 seasonal influenza isolates which display H274Y associated oseltamivir-resistance. Furthermore, the emergence of novel H1N1 raises the potential that additional reassortments can occur, resulting in drug resistant virus. Thus, additional antiviral approaches are urgently needed. DAS181 (Fludase), a sialidase fusion protein, has been shown to have inhibitory activity against a large number of seasonal influenza strains and a highly pathogenic avian influenza (HPAI) strain (H5N1). Here, we examine the in vitro activity of DAS181 against a panel of 2009 oseltamivir-resistant seasonal H1N1 clinical isolates. The activity of DAS181 against nine 2009, two 2007, and two 2004 clinical isolates of seasonal IFV H1N1 was examined using plaque number reduction assay on MDCK cells. DAS181 strongly inhibited all tested isolates. EC50 values remained constant against isolates from 2004, 2007, and 2009, suggesting that there was no change in DAS181 sensitivity over time. As expected, all 2007 and 2009 isolates were resistant to oseltamivir, consistent with the identification of the H274Y mutation in the NA gene of all these isolates. Interestingly, several of the 2007 and 2009 isolates also exhibited reduced sensitivity to zanamivir, and accompanying HA mutations near the sialic acid binding site were observed. DAS181 inhibits IFV that is resistant to NAIs. Thus, DAS181 may offer an alternative therapeutic option for seasonal or pandemic IFVs that become resistant to currently available antiviral drugs.

Propofol Phosphate, a Water-Soluble Propofol Prodrug: In Vivo Evaluation

After a single IV injection of the water-soluble propofol prodrug propofol phosphate (PP) in mice, rats, rabbits, and pigs, propofol was produced rapidly (1–15 min), inducing dose-dependent sedative effects. In mice, the hypnotic dose (HD50), lethal dose (LD50), and safety index (defined as a ratio: LD50/HD50) were 165.4 mg/kg, 600.6 mg/kg, and 3.6, respectively. Propofol was produced with half-lives of 5.3 ± 0.6 min in rats, 2.1 ± 0.6 min in rabbits, and 4.4 ± 2.4 min in pigs. The maximal concentration was dose and species dependent. The elimination half-life was 24 ± 12 min in rats, 21 ± 16 min in rabbits, and 225 ± 56 min in pigs. Propofol generated from PP produced pharmacological effects similar to those described in the literature. We found a correlation between PP dose and duration of sedation with propofol concentrations larger than 1.0 &mgr;g/mL, which produced somnolence and sedation in rats and pigs. Adequate sedation and, at large enough doses, anesthetic-level sedation were produced after the administration of PP. Overall, PP, the water-soluble prodrug of propofol, seems to be a viable development candidate for sedative and anesthetic applications.

Targeting pandemic influenza: a primer on influenza antivirals and drug resistance

The emergence of the 2009 H1N1 pandemic influenza A virus, as well as constant antigenic drift of seasonal influenza, underscores the remarkable versatility of this virus in adapting to the human population. While vaccines are the principal public health defence against influenza, rapid vaccine development can be a daunting task. Antiviral drugs offer the promise of inhibiting influenza regardless of its genetic variations. However, the rapid rise of resistance to several antivirals has highlighted the need for developing novel therapeutics with reduced drug resistance potential. In this review, we will summarize the effects of the currently licensed anti-influenza drugs as well as the candidates in development against the seasonal and the 2009 H1N1 pandemic influenza A virus with an emphasis on drug resistance.

Enhancement of HIV type 1 antigen-specific CD4+ T cell memory in subjects with chronic HIV type 1 infection receiving an HIV type 1 immunogen.

We examined HIV-1 specific memory helper T immune responses in chronically HIV-infected subjects who received an immune-based therapy (HIV-1 immunogen, Remune). Subjects in this study exhibited significant increases (p < 0.05) in the frequency of helper T memory cells expressing interferon gamma (IFN-gamma) and tumor necrosis factor alpha (TNF-alpha) in response to HIV-1 antigens in vitro. The frequencies of HIV-specific memory T cells increased after successive immunizations and exhibited a correlation with the standard tritiated thymidine incorporation lymphocyte proliferation assay (r = 0.72, p < 0.0008). These results support the notion that HIV-specific memory immune responses can be stimulated in subjects with chronic HIV infection. Further investigations are warranted to determine whether the induction of such responses is associated with virologic control.