Characterization of prefusion-F-specific antibodies elicited by natural infection with human metapneumovirus.

Human metapneumovirus (hMPV) is a major cause of acute respiratory infections in infants and older adults, for which no vaccines or therapeutics are available. The viral fusion (F) glycoprotein is required for entry and is the primary target of neutralizing antibodies; however, little is known about the humoral immune response generated from natural infection. Here, using prefusion-stabilized F proteins to interrogate memory B cells from two older adults, we obtain over 700 paired non-IgM antibody sequences representing 563 clonotypes, indicative of a highly polyclonal response.

Pan-SARS neutralizing responses after third boost vaccination in non-human primate immunogenicity model.

The emergence of SARS-CoV-2 variants, especially Beta and Delta, has raised concerns about the reduced protection from previous infection or vaccination based on the original Wuhan-Hu-1 (D614) virus. To identify promising regimens for inducing neutralizing titers towards new variants, we evaluated monovalent and bivalent mRNA vaccines either as primary vaccination or as a booster in nonhuman primates (NHPs). Two mRNA vaccines, D614-based MRT5500 and Beta-based MRT5500β, tested in sequential regimens or as a bivalent combination in naïve NHPs produced modest neutralizing titers to heterologous variants.

Development of multivalent mRNA vaccine candidates for seasonal or pandemic influenza.

Recent approval of mRNA vaccines for emergency use against COVID-19 is likely to promote rapid development of mRNA-based vaccines targeting a wide range of infectious diseases. Compared to conventional approaches, this vaccine modality promises comparable potency while substantially accelerating the pace of development and deployment of vaccine doses. Already demonstrated successfully for single antigen vaccines such as for COVID-19, this technology could be optimized for complex multi-antigen vaccines.

Influenza vaccination in the elderly boosts antibodies against conserved viral proteins and egg-produced glycans.

Seasonal influenza vaccination elicits a diminished adaptive immune response in the elderly, and the mechanisms of immunosenescence are not fully understood. Using Ig-Seq, we found a marked increase with age in the prevalence of cross-reactive (CR) serum antibodies that recognize both the H1N1 (vaccine-H1) and H3N2 (vaccine-H3) components of an egg-produced split influenza vaccine. CR antibodies accounted for 73% ± 18% of the serum vaccine responses in a cohort of elderly donors, 65% ± 15% in late middle-aged donors, and only 13% ± 5% in persons under 35 years of age.

Optimization of the Codon Pair Usage of Human Respiratory Syncytial Virus Paradoxically Resulted in Reduced Viral Replication and Reduced Immunogenicity.

We subjected various open reading frames (ORFs) in the genome of respiratory syncytial virus (RSV) to codon pair optimization (CPO) by increasing the content of codon pairs that are overrepresented in the human genome without changing overall codon usage and amino acid sequences. CPO has the potential to increase the expression of the encoded protein(s). Four viruses were made: Max A (with CPO of NS1, NS2, N, P, M, and SH ORFs), Max B (with CPO of G and F), Max L (with CPO of L), and Max FLC (with CPO of all ORFs except M2-1 and M2-2).

Comparison of adjuvants to optimize influenza neutralizing antibody responses.

Seasonal influenza vaccines represent a positive intervention to limit the spread of the virus and protect public health. Yet continual influenza evolution and its ability to evade immunity pose a constant threat. For these reasons, vaccines with improved potency and breadth of protection remain an important need.

A computationally designed H5 antigen shows immunological breadth of coverage and protects against drifting avian strains.

Since the first identification of the H5N1 Goose/Guangdong lineage in 1996, this highly pathogenic avian influenza virus has spread worldwide, becoming endemic in domestic poultry. Sporadic transmission to humans has raised concerns of a potential pandemic and underscores the need for a broad cross-protective influenza vaccine. Here, we tested our previously described methodology, termed Computationally Optimized Broadly Reactive Antigen (COBRA), to generate a novel hemagglutinin (HA) gene, termed COBRA-2, that was based on H5 HA sequences from 2005 to 2006.

Elicitation of Protective Antibodies against 20 Years of Future H3N2 Cocirculating Influenza Virus Variants in Ferrets Preimmune to Historical H3N2 Influenza Viruses.

The vast majority of people already have preexisting immune responses to influenza viruses from one or more subtypes. However, almost all preclinical studies evaluate new influenza vaccine candidates in immunologically naive animals. Recently, our group demonstrated that priming naive ferrets with broadly reactive H1 COBRA HA-based vaccines boosted preexisting antibodies induced by wild-type H1N1 virus infections.

Development of a Pan-H1 Influenza Vaccine.

The efficacy of current seasonal influenza vaccines varies greatly, depending on the match to circulating viruses. Although most vaccines elicit strain-specific responses, some present cross-reactive epitopes that elicit antibodies against diverse viruses and remain unchanged and effective for several years. To determine whether combinations of specific H1 hemagglutinin (HA) antigens stimulate immune responses that protect against diverse H1 influenza viruses, we evaluated the antibody responses elicited by HA-ferritin nanoparticles derived from six evolutionarily divergent H1 sequences and two computationally optimized broadly reactive antigen (COBRA) HA antigens.

Effect of genetic background and delivery route on the preclinical properties of a live attenuated RSV vaccine.

A safe and effective vaccine against RSV remains an important unmet public health need. Intranasally (IN) delivered live-attenuated vaccines represent the most extensively studied approach for immunization of RSV-naïve infants and children, however, achieving an effective balance of attenuation and immunogenicity has proven challenging. Here we report pre-clinical immunogenicity and efficacy data utilizing a live-attenuated vaccine candidate, RGΔM2-2, which was obtained by deleting the M2-2 open reading frame from the genome of the MSA1 clinical isolate.

Computationally Optimized Broadly Reactive Hemagglutinin Elicits Hemagglutination Inhibition Antibodies against a Panel of H3N2 Influenza Virus Cocirculating Variants.

Each influenza season, a set of wild-type viruses, representing one H1N1, one H3N2, and one to two influenza B isolates, are selected for inclusion in the annual seasonal influenza vaccine. In order to develop broadly reactive subtype-specific influenza vaccines, a methodology called computationally optimized broadly reactive antigens (COBRA) was used to design novel hemagglutinin (HA) vaccine immunogens. COBRA technology was effectively used to design HA immunogens that elicited antibodies that neutralized H5N1 and H1N1 isolates.

Elicitation of Protective Antibodies against a Broad Panel of H1N1 Viruses in Ferrets Preimmune to Historical H1N1 Influenza Viruses.

Most preclinical animal studies test influenza vaccines in immunologically naive animal models, even though the results of vaccination may not accurately reflect the effectiveness of vaccine candidates in humans that have preexisting immunity to influenza. In this study, novel, broadly reactive influenza vaccine candidates were assessed in preimmune ferrets. These animals were infected with different H1N1 isolates before being vaccinated or infected with another influenza virus.

Genetic stability of genome-scale deoptimized RNA virus vaccine candidates under selective pressure.

Recoding viral genomes by numerous synonymous but suboptimal substitutions provides live attenuated vaccine candidates. These vaccine candidates should have a low risk of deattenuation because of the many changes involved. However, their genetic stability under selective pressure is largely unknown.

Core bead chromatography for preparation of highly pure, infectious respiratory syncytial virus in the negative purification mode.

Respiratory syncytial virus (RSV) is an important human pathogen, and is the most frequent viral cause of severe respiratory disease in infants. In addition, it is increasingly being recognized as an important cause of respiratory disease in the elderly and immunocompromised. Although a passive prophylactic treatment does exist for high-risk neonates and children, the overall disease burden warrants the development of a safe and effective prophylactic vaccine for use in otherwise healthy newborns and children.

CX3CR1 Is Expressed in Differentiated Human Ciliated Airway Cells and Co-Localizes with Respiratory Syncytial Virus on Cilia in a G Protein-Dependent Manner.

Respiratory syncytial virus (RSV) is the principal cause of bronchiolitis in infants and a significant healthcare problem. The RSV Glycoprotein (G) mediates attachment of the virus to the cell membrane, which facilitates interaction of the RSV Fusion (F) protein with nucleolin, thereby triggering fusion of the viral and cellular membranes. However, a host protein ligand for G has not yet been identified.

Attenuation of human respiratory syncytial virus by genome-scale codon-pair deoptimization.

Human respiratory syncytial virus (RSV) is the most important viral agent of serious pediatric respiratory-tract disease worldwide. A vaccine or generally effective antiviral drug is not yet available. We designed new live attenuated RSV vaccine candidates by codon-pair deoptimization (CPD).

Immunogenicity and efficacy of intramuscular replication-defective and subunit vaccines against herpes simplex virus type 2 in the mouse genital model.

Herpes simplex virus type 2 (HSV-2) is a sexually transmitted virus that is highly prevalent worldwide, causing a range of symptoms that result in significant healthcare costs and human suffering. ACAM529 is a replication-defective vaccine candidate prepared by growing the previously described dl5-29 on a cell line appropriate for GMP manufacturing. This vaccine, when administered subcutaneously, was previously shown to protect mice from a lethal vaginal HSV-2 challenge and to afford better protection than adjuvanted glycoprotein D (gD) in guinea pigs.

Respiratory tract immunization of non-human primates with a Newcastle disease virus-vectored vaccine candidate against Ebola virus elicits a neutralizing antibody response.

We previously developed a respiratory tract vaccine candidate against Ebola virus (EBOV) based on human parainfluenza virus type 3 (HPIV3), a respiratory paramyxovirus, expressing the EBOV GP envelope protein (HPIV3/GP) from an added gene. Two doses of this vaccine candidate delivered by the intranasal and intratracheal route protected monkeys against intraperitoneal challenge with EBOV; however, concerns exist that the vaccine candidate may have reduced immunogenicity in the adult human population due to pre-existing immunity against HPIV3. Here we developed a new vaccine candidate (NDV/GP) based on Newcastle disease virus (NDV), an avian paramyxovirus that is antigenically distinct from human viral pathogens and is highly attenuated in monkeys.

Mucosal parainfluenza virus-vectored vaccine against Ebola virus replicates in the respiratory tract of vector-immune monkeys and is immunogenic.

We previously used human parainfluenza virus type 3 (HPIV3) as a vector to express the Ebola virus (EBOV) GP glycoprotein. The resulting HPIV3/EboGP vaccine was immunogenic and protective against EBOV challenge in a non-human primate model. However, it remained unclear whether the vaccine would be effective in adults due to preexisting immunity to HPIV3.

Contributions of the avian influenza virus HA, NA, and M2 surface proteins to the induction of neutralizing antibodies and protective immunity.

Highly pathogenic avian influenza virus (HPAIV) subtype H5N1 causes severe disease and mortality in poultry. Increased transmission of H5N1 HPAIV from birds to humans is a serious threat to public health. We evaluated the individual contributions of each of the three HPAIV surface proteins, namely, the hemagglutinin (HA), the neuraminidase (NA), and the M2 proteins, to the induction of HPAIV-neutralizing serum antibodies and protective immunity in chickens.

Newcastle disease virus-vectored vaccines expressing the hemagglutinin or neuraminidase protein of H5N1 highly pathogenic avian influenza virus protect against virus challenge in monkeys.

H5N1 highly pathogenic avian influenza virus (HPAIV) causes periodic outbreaks in humans, resulting in severe infections with a high (60%) incidence of mortality. The circulating strains have low human-to-human transmissibility; however, widespread concerns exist that enhanced transmission due to mutations could lead to a global pandemic. We previously engineered Newcastle disease virus (NDV), an avian paramyxovirus, as a vector to express the HPAIV hemagglutinin (HA) protein, and we showed that this vaccine (NDV/HA) induced a high level of HPAIV-specific mucosal and serum antibodies in primates when administered through the respiratory tract.

Delivery to the lower respiratory tract is required for effective immunization with Newcastle disease virus-vectored vaccines intended for humans.

Newcastle disease virus (NDV), an avian virus, is being evaluated for the development of vectored human vaccines against emerging pathogens. Previous studies of NDV-vectored vaccines in a mouse model suggested their potency after delivery by injection or by the intranasal route. We compared the efficacy of various routes of delivery of NDV-vectored vaccines in a non-human primate model.