Cerebrospinal fluid from Alzheimer's disease patients promotes tau aggregation in transgenic mice.

Tau is a microtubule stabilizing protein that forms aggregates in Alzheimer's disease (AD). Tau derived from AD patients' brains induces tau aggregation in a prion-like manner when injected into susceptible mouse models.Here we investigated whether cerebrospinal fluid (CSF) collected from patients diagnosed with probable AD or mild cognitive impairment (MCI) likely due to AD harbors a prion-like tau seeding potential. CSF was injected intrahippocampally into young P301S tau transgenic mice. CSF obtained from AD or MCI patients increased hippocampal tau hyperphosphorylation and tau tangle formation in these mice at 4 months post-seeding. Tau pathology was also accentuated in the contralateral hippocampus, and in anterior and posterior directions, indicative of spreading.We provide first evidence for in vivo prion-like properties of AD patients' CSF, accelerating tau pathology in susceptible tau transgenic mice. This demonstrates that biologically active tau seeds reach the CSF compartment in AD. Further studies may help to evaluate strain specific properties of CSF derived tau bioseeds, and to assess their diagnostic potential.

The Candidate Blood-stage Malaria Vaccine P27A Induces a Robust Humoral Response in a Fast Track to the Field Phase 1 Trial in Exposed and Nonexposed Volunteers.

Background: P27A is an unstructured 104mer synthetic peptide from Plasmodium falciparum trophozoite exported protein 1 (TEX1), the target of human antibodies inhibiting parasite growth. The present project aimed at evaluating the safety and immunogenicity of P27A peptide vaccine in malaria-nonexposed European and malaria-exposed African adults. Methods: This study was designed as a staggered, fast-track, randomized, antigen and adjuvant dose-finding, multicenter phase 1a/1b trial, conducted in Switzerland and Tanzania. P27A antigen (10 or 50 µg), adjuvanted with Alhydrogel or glucopyranosil lipid adjuvant stable emulsion (GLA-SE; 2.5 or 5 µg), or control rabies vaccine (Verorab) were administered intramuscularly to 16 malaria-nonexposed and 40 malaria-exposed subjects on days 0, 28, and 56. Local and systemic adverse events (AEs) as well as humoral and cellular immune responses were assessed after each injection and during the 34-week follow-up. Results: Most AEs were mild to moderate and resolved completely within 48 hours. Systemic AEs were more frequent in the formulation with alum as compared to GLA-SE, whereas local AEs were more frequent after GLA-SE. No serious AEs occurred. Supported by a mixed Th1/Th2 cell-mediated immunity, P27A induced a marked specific antibody response able to recognize TEX1 in infected erythrocytes and to inhibit parasite growth through an antibody-dependent cellular inhibition mechanism. Incidence of AEs and antibody responses were significantly lower in malaria-exposed Tanzanian subjects than in nonexposed European subjects. Conclusions: The candidate vaccine P27A was safe and induced a particularly robust immunogenic response in combination with GLA-SE. This formulation should be considered for future efficacy trials. Clinical Trials Registration: NCT01949909, PACTR201310000683408.

Safety and immunogenicity of a chimpanzee adenovirus-vectored Ebola vaccine in healthy adults: a randomised, double-blind, placebo-controlled, dose-finding, phase 1/2a study.

BACKGROUND: The ongoing Ebola outbreak led to accelerated efforts to test vaccine candidates. On the basis of a request by WHO, we aimed to assess the safety and immunogenicity of the monovalent, recombinant, chimpanzee adenovirus type-3 vector-based Ebola Zaire vaccine (ChAd3-EBO-Z). METHODS: We did this randomised, double-blind, placebo-controlled, dose-finding, phase 1/2a trial at the Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland. Participants (aged 18-65 years) were randomly assigned (2:2:1), via two computer-generated randomisation lists for individuals potentially deployed in endemic areas and those not deployed, to receive a single intramuscular dose of high-dose vaccine (5 × 10(10) viral particles), low-dose vaccine (2·5 × 10(10) viral particles), or placebo. Deployed participants were allocated to only the vaccine groups. Group allocation was concealed from non-deployed participants, investigators, and outcome assessors. The safety evaluation was not masked for potentially deployed participants, who were therefore not included in the safety analysis for comparison between the vaccine doses and placebo, but were pooled with the non-deployed group to compare immunogenicity. The main objectives were safety and immunogenicity of ChAd3-EBO-Z. We did analysis by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT02289027. FINDINGS: Between Oct 24, 2014, and June 22, 2015, we randomly assigned 120 participants, of whom 18 (15%) were potentially deployed and 102 (85%) were non-deployed, to receive high-dose vaccine (n=49), low-dose vaccine (n=51), or placebo (n=20). Participants were followed up for 6 months. No vaccine-related serious adverse events were reported. We recorded local adverse events in 30 (75%) of 40 participants in the high-dose group, 33 (79%) of 42 participants in the low-dose group, and five (25%) of 20 participants in the placebo group. Fatigue or malaise was the most common systemic adverse event, reported in 25 (62%) participants in the high-dose group, 25 (60%) participants in the low-dose group, and five (25%) participants in the placebo group, followed by headache, reported in 23 (57%), 25 (60%), and three (15%) participants, respectively. Fever occurred 24 h after injection in 12 (30%) participants in the high-dose group and 11 (26%) participants in the low-dose group versus one (5%) participant in the placebo group. Geometric mean concentrations of IgG antibodies against Ebola glycoprotein peaked on day 28 at 51 µg/mL (95% CI 41·1-63·3) in the high-dose group, 44·9 µg/mL (25·8-56·3) in the low-dose group, and 5·2 µg/mL (3·5-7·6) in the placebo group, with respective response rates of 96% (95% CI 85·7-99·5), 96% (86·5-99·5), and 5% (0·1-24·9). Geometric mean concentrations decreased by day 180 to 25·5 µg/mL (95% CI 20·6-31·5) in the high-dose group, 22·1 µg/mL (19·3-28·6) in the low-dose group, and 3·2 µg/mL (2·4-4·9) in the placebo group. 28 (57%) participants given high-dose vaccine and 31 (61%) participants given low-dose vaccine developed glycoprotein-specific CD4 cell responses, and 33 (67%) and 35 (69%), respectively, developed CD8 responses. INTERPRETATION: ChAd3-EBO-Z was safe and well tolerated, although mild to moderate systemic adverse events were common. A single dose was immunogenic in almost all vaccine recipients. Antibody responses were still significantly present at 6 months. There was no significant difference between doses for safety and immunogenicity outcomes. This acceptable safety profile provides a reliable basis to proceed with phase 2 and phase 3 efficacy trials in Africa. FUNDING: Swiss State Secretariat for Education, Research and Innovation (SERI), through the EU Horizon 2020 Research and Innovation Programme.

Safety of human immunisation with a live-attenuated Mycobacterium tuberculosis vaccine: a randomised, double-blind, controlled phase I trial.

BACKGROUND: Tuberculosis remains one of the world's deadliest transmissible diseases despite widespread use of the BCG vaccine. MTBVAC is a new live tuberculosis vaccine based on genetically attenuated Mycobacterium tuberculosis that expresses most antigens present in human isolates of M tuberculosis. We aimed to compare the safety of MTBVAC with BCG in healthy adult volunteers. METHODS: We did this single-centre, randomised, double-blind, controlled phase 1 study at the Centre Hospitalier Universitaire Vaudois (CHUV; Lausanne, Switzerland). Volunteers were eligible for inclusion if they were aged 18-45 years, clinically healthy, HIV-negative and tuberculosis-negative, and had no history of active tuberculosis, chemoprophylaxis for tuberculosis, or BCG vaccination. Volunteers fulfilling the inclusion criteria were randomly assigned to three cohorts in a dose-escalation manner. Randomisation was done centrally by the CHUV Pharmacy and treatments were masked from the study team and volunteers. As participants were recruited within each cohort, they were randomly assigned 3:1 to receive MTBVAC or BCG. Of the participants allocated MTBVAC, those in the first cohort received 5 × 10(3) colony forming units (CFU) MTBVAC, those in the second cohort received 5 × 10(4) CFU MTBVAC, and those in the third cohort received 5 × 10(5) CFU MTBVAC. In all cohorts, participants assigned to receive BCG were given 5 × 10(5) CFU BCG. Each participant received a single intradermal injection of their assigned vaccine in 0·1 mL sterile water in their non-dominant arm. The primary outcome was safety in all vaccinated participants. Secondary outcomes included whole blood cell-mediated immune response to live MTBVAC and BCG, and interferon γ release assays (IGRA) of peripheral blood mononuclear cells. This trial is registered with ClinicalTrials.gov, number NCT02013245. FINDINGS: Between Jan 23, 2013, and Nov 6, 2013, we enrolled 36 volunteers into three cohorts, each of which consisted of nine participants who received MTBVAC and three who received BCG. 34 volunteers completed the trial. The safety of vaccination with MTBVAC at all doses was similar to that of BCG, and vaccination did not induce any serious adverse events. All individuals were IGRA negative at the end of follow-up (day 210). After whole blood stimulation with live MTBVAC or BCG, MTBVAC was at least as immunogenic as BCG. At the same dose as BCG (5×10(5) CFU), although no statistical significance could be achieved, there were more responders in the MTBVAC group than in the BCG group, with a greater frequency of polyfunctional CD4+ central memory T cells. INTERPRETATION: To our knowledge, MTBVAC is the first live-attenuated M tuberculosis vaccine to reach clinical assessment, showing similar safety to BCG. MTBVAC seemed to be at least as immunogenic as BCG, but the study was not powered to investigate this outcome. Further plans to use more immunogenicity endpoints in a larger number of volunteers (adults and adolescents) are underway, with the aim to thoroughly characterise and potentially distinguish immunogenicity between MTBVAC and BCG in tuberculosis-endemic countries. Combined with an excellent safety profile, these data support advanced clinical development in high-burden tuberculosis endemic countries. FUNDING: Biofabri and Bill & Melinda Gates Foundation through the TuBerculosis Vaccine Initiative (TBVI).