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We report cellular nanosponges as an effective medical countermeasure to the SARS-CoV-2 virus. Two types of cellular nanosponges are made of the plasma membranes derived from human lung epithelial type II cells or human macrophages. These nanosponges display the same protein receptors, both identified and unidentified, required by SARS-CoV-2 for cellular entry. It is shown that, following incubation with the nanosponges, SARS-CoV-2 is neutralized and unable to infect cells. Crucially, the nanosponge platform is agnostic to viral mutations and potentially viral species, as well. As long as the target of the virus remains the identified host cell, the nanosponges will be able to neutralize the virus.

Marburg virus (MARV) causes a severe hemorrhagic fever disease in primates with mortality rates in humans of up to 90%. MARV has been identified as a category A bioterrorism agent by the Centers for Disease Control and Prevention (CDC) and priority pathogen A by the National Institute of Allergy and Infectious Diseases (NIAID), needing urgent research and development of countermeasures because of the high public health risk it poses. The recent cases of MARV in West Africa underscore the substantial outbreak potential of this virus. The potential for cross-border spread, as had occurred during the 2014–2016 Ebola virus outbreak, illustrates the critical need for MARV vaccines. To support regulatory approval of the chimpanzee adenovirus 3 (ChAd3)–MARV vaccine that has completed phase 1 trials, we showed that the nonreplicating ChAd3 vector, which has a demonstrated safety profile in humans, protected against a uniformly lethal challenge with MARV/Ang. Protective immunity was achieved within 7 days of vaccination and was maintained through 1 year after vaccination. Antigen-specific antibodies were an immune correlate of protection in the acute challenge model, and their concentration was predictive of protection. These results demonstrate that a single-shot ChAd3-MARV vaccine generated a protective immune response that was both rapid and durable with an immune correlate of protection that will support advanced clinical development.

We have developed a robust RNA sequencing method for generating complete de novoassemblies with intra-host variant calls of Lassa and Ebola virus genomes in clinical and biological samples. Our method uses targeted RNase H-based digestion to remove contaminating poly(rA) carrier and ribosomal RNA. This depletion step improves both the quality of data and quantity of informative reads in unbiased total RNA sequencing libraries. We have also developed a hybrid-selection protocol to further enrich the viral content of sequencing libraries. These protocols have enabled rapid deep sequencing of both Lassa and Ebola virus and are broadly applicable to other viral genomics studies.

We previously showed that small interfering RNAs (siRNAs) targeting the Zaire Ebola virus (ZEBOV) RNA polymerase L protein formulated in stable nucleic acid-lipid particles (SNALPs) completely protected guineapigs when administered shortly after a lethal ZEBOV challenge. Although rodent models of ZEBOV infection are useful for screening prospective countermeasures, they are frequently not useful for prediction of efficacy in the more stringent non-human primate models. We therefore assessed the efficacy of modified non-immunostimulatory siRNAs in a uniformly lethal non-human primate model of ZEBOV haemorrhagic fever.

The coronavirus disease 2019 (COVID‐19) pandemic demonstrates the importance of generating safe and efficacious vaccines that can be rapidly deployed against emerging pathogens. Subunit vaccines are considered among the safest, but proteins used in these typically lack strong immunogenicity, leading to poor immune responses. Here, a biomaterial COVID‐19 vaccine based on a mesoporous silica rods (MSRs) platform is described. MSRs loaded with granulocyte‐macrophage colony‐stimulating factor (GM‐CSF), the toll‐like receptor 4 (TLR‐4) agonist monophosphoryl lipid A (MPLA), and SARS‐CoV‐2 viral protein antigens slowly release their cargo and form subcutaneous scaffolds that locally recruit and activate antigen‐presenting cells (APCs) for the generation of adaptive immunity. MSR‐based vaccines generate robust and durable cellular and humoral responses against SARS‐CoV‐2 antigens, including the poorly immunogenic receptor binding domain (RBD) of the spike (S) protein. Persistent antibodies over the course of 8 months are found in all vaccine configurations tested and robust in vitro viral neutralization is observed both in a prime‐boost and a single‐dose regimen. These vaccines can be fully formulated ahead of time or stored lyophilized and reconstituted with an antigen mixture moments before injection, which can facilitate its rapid deployment against emerging SARS‐CoV‐2 variants or new pathogens. Together, the data show a promising COVID‐19 vaccine candidate and a generally adaptable vaccine platform against infectious pathogens. Mesoporous silica rods (MSRs) scaffolds are used as a platform to induce adaptive immunity against SARS‐CoV‐2 antigens. Sustained delivery of GM‐CSF, MPLA, and a variety of SARS‐CoV‐2 subunit immunogens from the MSR vaccine recruite immune cells into the scaffolds and consistently induce antigen‐specific long‐lasting antibodies, cytotoxic T lymphocyte responses (CTL), and viral neutralization in vitro.

Gram-negative flagellin, a Toll-like receptor 5 (TLR5) agonist, is a potent inducer of innate immune effectors such as cytokines and nitric oxide. In the lung, flagellin induces a localized and transient innate immune response characterized by neutrophil infiltration and the production of cytokines and chemokines. In view of the extraordinary potency of flagellin as an inducer of innate immunity and the contribution of innate responses to the development of adaptive immunity, we evaluated the efficacy of recombinant Salmonella flagellin as an adjuvant in an acellular plague vaccine. Mice immunized intranasally or intratracheally with the F1 antigen of Yersinia pestis and flagellin exhibited dramatic increases in anti-F1 plasma immunoglobulin G (IgG) titers that remained stable over time. In contrast, control mice had low or undetectable antibody responses. The IgG1/IgG2a ratio of antibody titers against F1 in immunized mice is consistent with a Th2 bias. However, no significant antigen-specific IgE production was detected. Interferons, tumor necrosis factor alpha, and interleukin-6 were not essential for the adjuvant effects of flagellin. Preexisting antiflagellin antibodies had no significant effect on the adjuvant activity of flagellin. Importantly, intranasal immunization with flagellin and the F1 antigen was protective against intranasal challenge with virulent Y. pestis CO92, with 93 to 100% survival of immunized mice. Lastly, vaccination of cynomolgus monkeys with flagellin and a fusion of the F1 and V antigens of Y. pestis induced a robust antigen-specific IgG antibody response.

ABSTRACTNonsurgical intratracheal instillation of 1 μg of purified, recombinant flagellin in several strains of mice stimulated a transient innate immune response in the lung characterized by the infiltration of neutrophils and the rapid production of tumor necrosis factor alpha, interleukin 6, granulocyte colony-stimulating factor, and the chemokines keratinocyte-derived chemokine, MIP1α, and MIP-2.

Cellular binding and entry of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are mediated by its spike glycoprotein (S protein), which binds with not only the human angiotensin-converting enzyme 2 (ACE2) receptor but also glycosaminoglycans such as heparin. Cell membrane-coated nanoparticles (“cellular nanosponges”) mimic the host cells to attract and neutralize SARS-CoV-2 through natural cellular receptors, leading to a broad-spectrum antiviral strategy. Herein, we show that increasing surface heparin density on the cellular nanosponges can promote their inhibition against SARS-CoV-2. Specifically, cellular nanosponges are made with azido-expressing host cell membranes followed by conjugating heparin to the nanosponge surfaces. Cellular nanosponges with a higher heparin density have a larger binding capacity with viral S proteins and a significantly higher inhibition efficacy against SARS-CoV-2 infectivity. Overall, surface glycan engineering of host-mimicking cellular nanosponges is a facile method to enhance SARS-CoV-2 inhibition. This approach can be readily generalized to promote the inhibition of other glycan-dependent viruses.

Current molecular tests that identify infection with high-consequence viruses such as Ebola virus and Marburg virus are based on the detection of virus material in the blood. These viruses do not undergo significant early replication in the blood and, instead, replicate in organs such as the liver and spleen. Thus, virus begins to accumulate in the blood only after significant replication has already occurred in those organs, making viremia an indicator of infection only after initial stages have become established. Here, we show that a multianalyte assay can correctly identify the infectious agent in nonhuman primates (NHPs) prior to viremia through tracking host infection response transcripts. This illustrates that a single-tube, sample-to-answer format assay could be used to advance the time at which the type of infection can be determined and thereby improve outcomes.

A multiplexed point-of-care diagnostic using surface-enhanced Raman scattering detects Ebola, Lassa, and malaria in blood and serum samples.