Early indicators of exposure to biological threat agents using host gene profiles in peripheral blood mononuclear cells

<p>Abstract</p> <p>Background</p> <p>Effective prophylaxis and treatment for infections caused by biological threat agents (BTA) rely upon early diagnosis and rapid initiation of therapy. Most methods for identifying pathogens in body fluids and tissues require that the pathogen proliferate to detectable and dangerous levels, thereby delaying diagnosis and treatment, especially during the prelatent stages when symptoms for most BTA are indistinguishable flu-like signs.</p> <p>Methods</p> <p>To detect exposures to the various pathogens more rapidly, especially during these early stages, we evaluated a suite of host responses to biological threat agents using global gene expression profiling on complementary DNA arrays.</p> <p>Results</p> <p>We found that certain gene expression patterns were unique to each pathogen and that other gene changes occurred in response to multiple agents, perhaps relating to the eventual course of illness. Nonhuman primates were exposed to some pathogens and the <it>in vitro</it> and <it>in vivo</it> findings were compared. We found major gene expression changes at the earliest times tested post exposure to aerosolized <it>B. anthracis </it>spores and 30 min post exposure to a bacterial toxin.</p> <p>Conclusion</p> <p>Host gene expression patterns have the potential to serve as diagnostic markers or predict the course of impending illness and may lead to new stage-appropriate therapeutic strategies to ameliorate the devastating effects of exposure to biothreat agents.</p

Vaccine efficacy of ALVAC-HIV and bivalent subtype C gp120–MF59 in adults

BACKGROUND : A safe, effective vaccine is essential to eradicating human immunodeficiency virus (HIV) infection. A canarypox–protein HIV vaccine regimen (ALVAC-HIV plus AIDSVAX B/E) showed modest efficacy in reducing infection in Thailand. An analogous regimen using HIV-1 subtype C virus showed potent humoral and cellular responses in a phase 1–2a trial in South Africa. Efficacy data and additional safety data were needed for this regimen in a larger population in South Africa. METHODS : In this phase 2b–3 trial, we randomly assigned 5404 adults without HIV-1 infection to receive the vaccine (2704 participants) or placebo (2700 participants). The vaccine regimen consisted of injections of ALVAC-HIV at months 0 and 1, followed by four booster injections of ALVAC-HIV plus bivalent subtype C gp120–MF59 adjuvant at months 3, 6, 12, and 18. The primary efficacy outcome was the occurrence of HIV-1 infection from randomization to 24 months. RESULTS : In January 2020, prespecified criteria for non-efficacy were met at an interim analysis; further vaccinations were subsequently halted. The median age of the trial participants was 24 years; 70% of the participants were women. The incidence of adverse events was similar in the vaccine and placebo groups. During the 24-month followup, HIV-1 infection was diagnosed in 138 participants in the vaccine group and in 133 in the placebo group (hazard ratio, 1.02; 95% confidence interval, 0.81 to 1.30; P = 0.84). CONCLUSIONS : The ALVAC–gp120 regimen did not prevent HIV-1 infection among participants in South Africa despite previous evidence of immunogenicity.Supported by grants (HHSN272201300033C and HHSN272201600012C) to Novartis Vaccines and Diagnostics (now part of the GlaxoSmithKline [GSK] Biologicals) by the National Institute of Allergy and Infectious Diseases (NIAID) of the National Institutes of Health (NIH) for the selection and process development of the two gp120 envelope proteins TV1.C and 1086.C; by the Bill and Melinda Gates Foundation Global Health Grant (OPP1017604) and NIAID for the manufacture and release of the gp120 clinical grade material; and by U.S. Public Health Service Grants — UM1 AI068614 to the HIV Vaccine Trials Network (HVTN), UM1 AI068635 to the HVTN Statistical and Data Management Center, and UM1 AI068618 to the HVTN Laboratory Center — from the NIAID. GSK Biologicals contributed financially to the provision of preexposure prophylaxis to trial participants. The South African Medical Research Council supported its affiliated research sites.http://www.nejm.orgam2022School of Health Systems and Public Health (SHSPH

Long term immunity to live attenuated Japanese encephalitis chimeric virus vaccine: Randomized, double-blind, 5-year phase II study in healthy adults

In a randomized, double-blind study, 202 healthy adults were randomized to receive a live, attenuated Japanese encephalitis chimeric virus vaccine (JE-CV) and placebo 28 days apart in a cross-over design. A subgroup of 98 volunteers received a JE-CV booster at month 6. Safety, immunogenicity and persistence of antibodies to month 60 were evaluated

Induction of Japanese encephalitis virus-specific cytotoxic T lymphocytes in humans by poxvirus-based JE vaccine candidates

Poxvirus-based recombinant Japanese encephalitis (JE) vaccine candidates, NYVAC-JEV and ALVAC-JEV, were examined for their ability to induce JE virus-specific cytotoxic T lymphocytes (CTLs) in a phase I clinical trial. These vaccine candidates encoded the JE virus premembrane (prM), envelope (E) and non-structural 1 (NS1) proteins. The volunteers received subcutaneous inoculations with each of these candidates on days 0 and 28, and blood was drawn 2 days before vaccination and on day 58. Anti-E and anti-NS1 antibodies were elicited in most vaccinees inoculated with NYVAC-JEV and in some vaccinees inoculated with ALVAC-JEV. Peripheral blood mononuclear cells (PBMCs) obtained from approximately one half of vaccines showed positive proliferation in response to stimulation with live JE virus. Cytotoxic assays demonstrated the presence of JE virus-specific CTLs in in vitro-stimulated PBMCs obtained from two NYVAC-JEV and two ALVAC-JEV vaccinees. Cell depletion tests using PBMCs from one NYVAC-JEV recipient indicated that the phenotype of CTLs was CD8+CD4-

Live Attenuated Chimeric Yellow Fever Dengue Type 2 (Chimeri Vax -DEN2) Vaccine: Phase 1 clinical trial for safety and immunogenicity

A randomized double-blind Phase I Trial was conducted to evaluate safety, tolerability, and immunogenicity of a yellow fever (YF)-dengue 2 (DEN2) chimera (ChimeriVax™-DEN2) in comparison to that of YF vaccine (YF-VAX®). Forty-two healthy YF naïve adults randomly received a single dose of either ChimeriVax™-DEN2 (high dose, 5 log plaque forming units [PFU] or low dose, 3 log PFU) or YF-VAXâ by the subcutaneous route (SC). To determine the effect of YF pre-immunity on the ChimeriVaxTM-DEN2 vaccine, 14 subjects previously vaccinated against YF received a high dose of ChimeriVax™-DEN2 as an open-label vaccine. Most adverse events were similar to YF-VAX® and of mild to moderate intensity, with no serious side-effects. One hundred percent and 92.3% of YF naïve subjects inoculated with 5.0 and 3.0 log10 PFU of ChimeriVaxTM-DEN2, respectively, seroconverted to wt DEN2 (strain 16681); 92% of subjects inoculated with YF-VAX® seroconverted to YF 17D virus but none of YF naïve subjects inoculated with ChimeriVax-DEN2 seroconverted to YF 17D virus. Low seroconversion rates to heterologous DEN serotypes 1, 3, and 4 were observed in YF naïve subjects inoculated with either ChimeriVax™-DEN2 or YF-VAX®. In contrast, 100% of YF immune subjects inoculated with ChimeriVax™-DEN2 seroconverted to all 4 DEN serotypes. Surprisingly, levels of neutralizing antibodies to DEN 1, 2, and 3 viruses in YF immune subjects persisted after 1 year. These data demonstrated that 1) the safety and immunogenicity profile of the ChimeriVax™-DEN2 vaccine is consistent with that of YF-VAX®, and 2) pre-immunity to YF virus does not interfere with ChimeriVaxTM-DEN2 immunization, but induces a long lasting and cross neutralizing antibody response to all 4 DEN serotypes. The latter observation can have practical implications toward development of a dengue vaccine

Concomitant or sequential administration of live attenuated japanese encephalitis chimeric virus vaccine and yellow fever 17D vaccine: Randomized double-blind phase II evaluation of safety and immunogenicity

A randomized, double-blind, study was conducted to evaluate the safety, tolerability and immunogenicity of a live attenuated Japanese encephalitis chimeric virus vaccine (JE-CV) co-administered with live attenuated yellow fever (YF) vaccine (YF-17D strain; Stamaril®, Sanofi Pasteur) or administered sequentially

Recombination and flavivirus vaccines: a commentary

A review article recently appeared in the Lancet by Seligman and Gould, in which the authors raise a safety concern for flavivirus vaccines based on possible recombination between wild-type viruses and live, attenuated vaccine viruses. Flaviviruses are small enveloped viruses with a single positive sense RNA genome containing a single long open reading frame encoding three structural and seven nonstructural genes. There is considerable controversy about whether recombination events occur between flaviviruses. Unfortunately, by emphasizing this remote and theoretical risk, rather than the potential public health benefits of new vaccines, the authors have provided an unbalanced view that may impede the progress of a number of promising live, attenuated vaccines under development. Over 2.5 billion people are at risk of dengue, and this disease has a total impact of the same order of magnitude as malaria, tuberculosis, bacterial meningitis and others. The World Health Organization (WHO) and the Gates Foundation have placed a high priority on the development and introduction of live, attenuated vaccines against Japanese encephalitis and dengue