Interferon‐induced transmembrane proteins (IFITMs) restrict infections by many viruses, but a subset of IFITMs enhance infections by specific coronaviruses through currently unknown mechanisms. We ...show that SARS‐CoV‐2 Spike‐pseudotyped virus and genuine SARS‐CoV‐2 infections are generally restricted by human and mouse IFITM1, IFITM2, and IFITM3, using gain‐ and loss‐of‐function approaches. Mechanistically, SARS‐CoV‐2 restriction occurred independently of IFITM3 S‐palmitoylation, indicating a restrictive capacity distinct from reported inhibition of other viruses. In contrast, the IFITM3 amphipathic helix and its amphipathic properties were required for virus restriction. Mutation of residues within the IFITM3 endocytosis‐promoting YxxФ motif converted human IFITM3 into an enhancer of SARS‐CoV‐2 infection, and cell‐to‐cell fusion assays confirmed the ability of endocytic mutants to enhance Spike‐mediated fusion with the plasma membrane. Overexpression of TMPRSS2, which increases plasma membrane fusion versus endosome fusion of SARS‐CoV‐2, attenuated IFITM3 restriction and converted amphipathic helix mutants into infection enhancers. In sum, we uncover new pro‐ and anti‐viral mechanisms of IFITM3, with clear distinctions drawn between enhancement of viral infection at the plasma membrane and amphipathicity‐based mechanisms used for endosomal SARS‐CoV‐2 restriction.
SYNOPSIS
Interferon‐induced transmembrane proteins (IFITMs) are generally restrictive of SARS‐CoV‐2 infection of cells. While IFITM3 inhibits endocytic entry of the virus, it enhances virus fusion at the plasma membrane.
IFITM1, 2, and 3 from mice and humans generally decrease infection by SARS‐CoV‐2.
Human IFITM3 inhibits infection at endosomes via a palmitoylation‐independent and amphipathicity‐dependent mechanism.
Human IFITM3 enhances virus fusion at the plasma membrane via an amphipathicity‐independent mechanism.
TMPRSS2 protease expression can shift the balance of IFITM3 activities toward enhancement of infection.
While IFITM‐family host‐cell antiviral factors generally restrict SARS‐CoV‐2 infection, human IFITM3 surprisingly exhibits both anti‐ and pro‐viral effects, inhibiting endocytic entry of the virus while also enhancing virus fusion at the plasma membrane.
Summary Background Cytomegalovirus reactivation occurs within 6 months in 60–70% of cytomegalovirus-seropositive patients after allogeneic haemopoietic stem-cell transplantation (HSCT), mainly due to ...immunosuppression associated with the procedure. Pre-emptive antiviral therapy reduces incidence of cytomegalovirus disease but can be toxic. To reduce the potential for disease and subsequent need for such antiviral drugs, we aimed to assess safety and efficacy of a cytomegalovirus therapeutic DNA vaccine compared with placebo. Methods In this exploratory double-blind, placebo-controlled, parallel group, phase 2 trial, up to 80 donor–recipient pairs and 80 unpaired recipients undergoing allogeneic HSCT were planned for enrolment at 16 transplant centres in the USA. Eligible recipients were cytomegalovirus-seropositive, 18–65 years old, without high-risk primary disease, T-cell depletion, previous vaccination for cytomegalovirus, or autoimmune diseases. We randomly allocated participants in both parallel groups in a 1:1 ratio to receive a cytomegalovirus therapeutic DNA vaccine (TransVax; Vical, San Diego, CA, USA) or placebo before conditioning and at 1, 3, and 6 months after transplantation. The vaccine contains plasmids encoding cytomegalovirus glycoprotein B and phosphoprotein 65 formulated with poloxamer CRL1005 and benzalkonium chloride. Randomisation was done by sequential allocation based on Pocock and Simon's method, and stratified by site, donor–recipient HLA matching status, and donor's cytomegalovirus serostatus. The primary outcome was the occurrence rate of clinically significant viraemia resulting in initiation of cytomegalovirus-specific antiviral therapy in the per-protocol assessable population. We assessed rates of adverse events in all participants who received at least one dose of vaccine or placebo. This study is registered with ClinicalTrials.gov , number NCT00285259. Findings We randomly allocated 108 participants (94 HSCT recipients and 14 paired donors) between June 29, 2006, and Dec 11, 2009. Enrolment of the paired arm was halted in February 2008 for logistical reasons. Safety was assessed in all participants; the efficacy population was restricted to 74 unpaired recipients. Groups were balanced for demographic and clinical variables. 19 (48%) of 40 vaccine recipients required cytomegalovirus-specific antiviral therapy, compared with 21 (62%) of 34 controls (p=0·145). However, during follow-up vaccine significantly reduced the occurrence and recurrence of cytomegalovirus viraemia and improved the time-to-event for viraemia episodes compared with placebo. The vaccine was well-tolerated; only one participant discontinued after an allergic reaction. Incidence of common adverse events after HSCT (eg, graft-versus-host disease or secondary infections) did not differ between groups. Interpretation We show proof of concept for an immunotherapeutic cytomegalovirus vaccine (TransVax) for clinically significant viraemia in the HSCT setting. The reported safety and efficacy outcomes support further development in a phase 3 trial, notwithstanding a lack of significant reduction in the use of cytomegalovirus-specific antiviral therapy compared with placebo in this phase 2 trial. Funding Vical and US National Institute of Allergy and Infectious Diseases.
Influenza virus activates cellular inflammasome pathways, which can be both beneficial and detrimental to infection outcomes. Here, we investigate the function of the inflammasome-activated, ...pore-forming protein gasdermin D (GSDMD) during infection. Ablation of GSDMD in knockout (KO) mice (Gsdmd
) significantly attenuates influenza virus-induced weight loss, lung dysfunction, lung histopathology, and mortality compared with wild type (WT) mice, despite similar viral loads. Infected Gsdmd
mice exhibit decreased inflammatory gene signatures shown by lung transcriptomics. Among these, diminished neutrophil gene activation signatures are corroborated by decreased detection of neutrophil elastase and myeloperoxidase in KO mouse lungs. Indeed, directly infected neutrophils are observed in vivo and infection of neutrophils in vitro induces release of DNA and tissue-damaging enzymes that is largely dependent on GSDMD. Neutrophil depletion in infected WT mice recapitulates the reductions in mortality, lung inflammation, and lung dysfunction observed in Gsdmd
animals, while depletion does not have additive protective effects in Gsdmd
mice. These findings implicate a function for GSDMD in promoting lung neutrophil responses that amplify influenza virus-induced inflammation and pathogenesis. Targeting the GSDMD/neutrophil axis may provide a therapeutic avenue for treating severe influenza.
The benefits of recombinant interleukin-12 (rIL-12) as a multifunctional cytokine and potential immunotherapy for cancer have been sought for decades based on its efficacy in multiple mouse models. ...Unexpected toxicity in the first phase 2 study required careful attention to revised dosing strategies. Despite some signs of efficacy since then, most rIL-12 clinical trials have encountered hurdles such as short terminal elimination half-life (T
), limited tumor microenvironment targeting, and substantial systemic toxicity. We developed a strategy to extend the rIL-12 T
that depends on binding albumin
to target tumor tissue, using single-chain rIL-12 linked to a fully human albumin binding (F
AB) domain (SON-1010). After initiating a dose-escalation trial in patients with cancer (SB101), a randomized, double-blind, placebo-controlled, single-ascending dose (SAD) phase 1 trial in healthy volunteers (SB102) was conducted.
SB102 (NCT05408572) focused on safety, tolerability, pharmacokinetic (PK), and pharmacodynamic (PD) endpoints. SON-1010 at 50-300 ng/kg or placebo administered subcutaneously on day 1 was studied at a ratio of 6:2, starting with two sentinels; participants were followed through day 29. Safety was reviewed after day 22, before enrolling the next cohort. A non-compartmental analysis of PK was performed and correlations with the PD results were explored, along with a comparison of the SON-1010 PK profile in SB101.
Participants receiving SON-1010 at 100 ng/kg or higher tolerated the injection but generally experienced more treatment-emergent adverse effects (TEAEs) than those receiving the lowest dose. All TEAEs were transient and no other dose relationship was noted. As expected with rIL-12, initial decreases in neutrophils and lymphocytes returned to baseline by days 9-11. PK analysis showed two-compartment elimination in SB102 with mean T
of 104 h, compared with one-compartment elimination in SB101, which correlated with prolonged but controlled and dose-related increases in interferon-gamma (IFNγ). There was no evidence of cytokine release syndrome based on minimal participant symptoms and responses observed with other cytokines.
SON-1010, a novel presentation for rIL-12, was safe and well-tolerated in healthy volunteers up to 300 ng/kg. Its extended half-life leads to a prolonged but controlled IFNγ response, which may be important for tumor control in patients.
https://clinicaltrials.gov/study/NCT05408572, identifier NCT05408572.
The potential synergy between interleukin-12 (IL-12) and IL-15 holds promise for more effective solid tumor immunotherapy. Nevertheless, previous clinical trials involving therapeutic cytokines have ...encountered obstacles such as short pharmacokinetics, limited tumor microenvironment (TME) targeting, and substantial systemic toxicity.
To address these challenges, we fused single-chain human IL-12 and native human IL-15 in
onto a fully human albumin binding (F
AB) domain single-chain antibody fragment (scFv). This novel fusion protein, IL12-F
AB-IL15 (SON-1210), is anticipated to amplify the therapeutic impact of interleukins and combination immunotherapies in human TME. The molecule was studied
and in animal models to assess its pharmacokinetics, potency, functional characteristics, safety, immune response, and efficacy.
SON-1210 demonstrated robust binding affinity to albumin and exhibited the anticipated
activity and tumor model efficacy that might be expected based on decades of research on native IL-12 and IL-15. Notably, in the B16F10 melanoma model (a non-immunogenic, relatively "cold" tumor), the murine counterpart of the construct, which had mouse (m) and human (h) cytokine sequences for the respective payloads (mIL12-F
AB-hIL15), outperformed equimolar doses of the co-administered native cytokines in a dose-dependent manner. A single dose caused a marked reduction in tumor growth that was concomitant with increased IFNγ levels; increased Th1, CTL, and activated NK cells; a shift in macrophages from the M2 to M1 phenotype; and a reduction in Treg cells. In addition, a repeat-dose non-human primate (NHP) toxicology study displayed excellent tolerability up to 62.5 µg/kg of SON-1210 administered three times, which was accompanied by the anticipated increases in IFNγ levels. Toxicokinetic analyses showed sustained serum levels of SON-1210, using a sandwich ELISA with anti-IL-15 for capture and biotinylated anti-IL-12 for detection, along with sustained IFNγ levels, indicating prolonged kinetics and biological activity.
Collectively, these findings support the suitability of SON-1210 for patient trials in terms of activity, efficacy, and safety, offering a promising opportunity for solid tumor immunotherapy. Linking cytokine payloads to a fully human albumin binding domain provides an indirect opportunity to target the TME using potent cytokines in
that can redirect the immune response and control tumor growth.
We conducted an open label, dose escalation Phase 1 clinical trial of a tetravalent dengue DNA vaccine (TVDV) formulated in Vaxfectin
to assess safety and immunogenicity. A total of 40 dengue- and ...flavivirus-naive volunteers received either low-dose (1 mg) TVDV alone (
= 10, group 1), low-dose TVDV (1 mg) formulated in Vaxfectin (
= 10, group 2), or high-dose TVDV (2 mg, group 3) formulated in Vaxfectin
(
= 20). Subjects were immunized intramuscularly with three doses on a 0-, 30-, 90-day schedule and monitored. Blood samples were obtained after each immunization and various time points thereafter to assess anti-dengue antibody and interferon gamma (IFNγ) T-cell immune responses. The most common adverse events (AEs) across all groups included mild to moderate pain and tenderness at the injection site, which typically resolved within 7 days. Common solicited signs and symptoms included fatigue (42.5%), headache (45%), and myalgias (47.5%). There were no serious AEs related to the vaccine or study procedures. No anti-dengue antibody responses were detected in group 1 subjects who received all three immunizations. There were minimal enzyme-linked immunosorbent assay and neutralizing antibody responses among groups 2 and 3 subjects who completed the immunization schedule. By contrast, IFNγ T-cell responses, regardless of serotype specificity, occurred in 70%, 50%, and 79% of subjects in groups 1, 2, and 3, respectively. The largest IFNγ T-cell responses were among group 3 subjects. We conclude that TVDV was safe and well-tolerated and elicited predominately anti-dengue T-cell IFNγ responses in a dose-related fashion.
The loss of half the U.S. supply of influenza vaccine due to contamination has created a critical shortage. Dose-sparing strategies that use intradermal delivery of vaccines may be one approach to ...consider.
We conducted a randomized, open-label trial outside the influenza season in 100 healthy adults 18 to 40 years of age to compare the immunogenicity and safety of intradermal immunization with influenza vaccine with standard intramuscular immunization. Subjects were randomly assigned to receive either a single intramuscular dose of 0.5 ml of trivalent influenza vaccine, containing at least 15 microg of hemagglutinin per strain, by means of a prefilled syringe or a single intradermal dose of 0.1 ml, containing at least 3 microg of hemagglutinin per strain, by means of a fine-gauge needle; both injections were in the deltoid region. Changes in the hemagglutination-inhibition (HAI) antibody titer were assessed by comparing geometric mean titers and fold increases relative to baseline values and by comparing changes in the seroconversion and seroprotection rates. Local and systemic adverse events were assessed after both types of vaccination.
Subjects who received an intradermal injection with one fifth the standard dose of influenza vaccine had increases in the geometric mean HAI titer by a factor of 15.2 for the H1N1 strain in the vaccine, 19.0 for the H3N2 strain, and 12.4 for the B strain on day 21, as compared with respective increases by a factor of 14.9, 7.1, and 15.3 for the intramuscular injection of the standard dose. Seroconversion and seroprotection rates were similar in the two groups on day 21, ranging from 66 to 82 percent and 84 to 100 percent, respectively. Local reactions were significantly more frequent among recipients of intradermal injections than among recipients of intramuscular injections, but such reactions were mild and transient.
In this study of young adults, intradermal administration of one fifth the standard intramuscular dose of an influenza vaccine elicited immunogenicity that was similar to or better than that elicited by intramuscular injection. Intradermal administration could be used to expand the supplies of influenza vaccine, but further studies are needed before this strategy can be recommended for routine use.
Folate receptor alpha (FRα) is overexpressed on >90% of high-grade epithelial ovarian cancers (EOC). Targeting FRα with antibody-drug conjugates has proven utility in the platinum-resistant setting. ...It is also a potential therapeutic target for immuno-oncologic agents, such as peptide vaccines that work primarily via adaptive and humoral immunity. We tested the hypothesis that FRα peptide immunization could improve outcomes in patients with EOC following response to platinum-based therapy.
We conducted a randomized, double-blind, multicenter, phase II study to evaluate the safety and efficacy of TPIV200 (a multi-epitope FRα peptide vaccine admixed with GM-CSF) versus GM-CSF alone in 120 women who did not have disease progression after at least 4 cycles of first-line platinum-based therapy. Patients were vaccinated intradermally once every 4 weeks up to 6 times, followed by a boosting period of 6 vaccinations at 12-week intervals. Primary endpoints included safety, tolerability, and progression free survival (PFS).
At study termination with a median follow-up of 15.2 months (range 1.2–28.4 months), 68 of 119 intention-to-treat patients had disease progression (55% in TPIV200 + GM-CSF arm and 59% in GM-CSF alone arm). The median PFS was 11.1 months (95% CI 8.3–16.6 months) with no significant difference between the treatment groups (10.9 months with TPIV200 + GM-CSF versus 11.1 months with GM-CSF, HR, 0.85; upper 90% CI 1.17. No patient experienced a ≥ grade 3 drug-related adverse event.
TPIV200 was well tolerated but was not associated with improved PFS. Additional studies are required to uncover potential synergies using multiepitope vaccines targeting FRα.
Trial Registration
NLM/NCBI Registry, NCT02978222, https://clinicaltrials.gov/search?term=NCT02978222.
•Patients with EOC were vaccinated with multiple antigenic folate receptor alpha (FRα) MHC class II peptides (TPIV200).•Immunization with TPIV200 was well-tolerated but did not increase progression-free survival or response rate.•While FRα is selectively expressed in EOC, timing of immunization or combination therapy may be needed to improve outcomes.
More than 26,000 cases of Ebola virus disease (EVD) have been reported in western Africa, with high mortality. Several patients have been medically evacuated to hospitals in the United States and ...Europe. Detailed clinical data are limited on the clinical course and management of patients with EVD outside western Africa.
To describe the clinical characteristics and management of a cluster of patients with EVD, including the first cases of Ebola virus (EBOV) infection acquired in the United States.
Retrospective clinical case series.
Three U.S. hospitals in September and October 2014.
First imported EVD case identified in the United States and 2 secondary EVD cases acquired in the United States in critical care nurses who cared for the index case patient.
Clinical recovery, EBOV RNA level, resolution of Ebola viremia, survival with discharge from hospital, or death.
The index patient had high EBOV RNA levels, developed respiratory and renal failure requiring critical care support, and died. Both patients with secondary EBOV infection had nonspecific signs and symptoms and developed moderate illness; EBOV RNA levels were moderate, and both patients recovered.
Both surviving patients received uncontrolled treatment with multiple investigational agents, including convalescent plasma, which limits generalizability of the results.
Early diagnosis, prompt initiation of supportive medical care, and moderate clinical illness likely contributed to successful outcomes in both survivors. The inability to determine the potential benefit of investigational therapies and the effect of patient-specific factors that may have contributed to less severe illness highlight the need for controlled clinical studies of these interventions, especially in the setting of a high level of supportive medical care.
None.
Preclinical data suggest that a "prime-boost" vaccine regimen using a target-expressing lentiviral vector for priming, followed by a recombinant protein boost, may be effective against cancer; ...however, this strategy has not been evaluated in a clinical setting. CMB305 is a prime-boost vaccine designed to induce a broad anti-NY-ESO-1 immune response. It is composed of LV305, which is an NY-ESO-1 expressing lentiviral vector, and G305, a recombinant adjuvanted NY-ESO-1 protein. This multicenter phase 1b, first-in-human trial evaluated CMB305 in patients with NY-ESO-1 expressing solid tumors. Safety was examined in a 3 + 3 dose-escalation design, followed by an expansion with CMB305 alone or in a combination with either oral metronomic cyclophosphamide or intratumoral injections of a toll-like receptor agonist (glucopyranosyl lipid A). Of the 79 patients who enrolled, 81.0% had sarcomas, 86.1% had metastatic disease, and 57.0% had progressive disease at study entry. The most common adverse events were fatigue (34.2%), nausea (26.6%), and injection-site pain (24.1%). In patients with soft tissue sarcomas, a disease control rate of 61.9% and an overall survival of 26.2 months (95% CI, 22.1-NA) were observed. CMB305 induced anti-NY-ESO-1 antibody and T-cell responses in 62.9% and 47.4% of patients, respectively. This is the first trial to test a prime-boost vaccine regimen in patients with advanced cancer. This approach is feasible, can be delivered safely, and with evidence of immune response as well as suggestion of clinical benefit.
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