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We explored the feasibility of collecting convalescent plasma for passive immunotherapy of Middle East respiratory syndrome coronavirus (MERS-CoV) infection by using ELISA to screen serum samples from 443 potential plasma donors: 196 patients with suspected or laboratory-confirmed MERS-CoV infection, 230 healthcare workers, and 17 household contacts exposed to MERS-CoV. ELISA-reactive samples were further tested by indirect fluorescent antibody and microneutralization assays. Of the 443 tested samples, 12 (2.7%) had a reactive ELISA result, and 9 of the 12 had reactive indirect fluorescent antibody and microneutralization assay titers. Undertaking clinical trials of convalescent plasma for passive immunotherapy of MERS-CoV infection may be feasible, but such trials would be challenging because of the small pool of potential donors with sufficiently high antibody titers. Alternative strategies to identify convalescent plasma donors with adequate antibody titers should be explored, including the sampling of serum from patients with more severe disease and sampling at earlier points during illness. [ABSTRACT FROM AUTHOR]

The article discusses the study on the effectiveness of transchromosomic bovine human immunoglobulins G (Tc hIgG) purified from the plasma of animals that received MERS-CoV vaccine in neutralizing the virus. The study reportedly involved bovine that were selected for health and genetic characteristics. The results revealed that Tc hIgG inhibits MERS-CoV.

Four distinct serotypes of dengue viruses (DENV) are the cause of re-emerging dengue fever (DF) and dengue hemorrhagic fever (DHF). Dengue circulation in the Caribbean has gone from none or single serotype to multiple serotypes co-circulating with reports of continuing cycles of progressively more severe disease in the region. Few studies have investigated dengue on Sint Eustatius. Blood samples were collected to determine the prevalence of antibodies against dengue in the Sint Eustatius population. Greater than 90% of the serum samples (184 of 204) were positive for anti-flavivirus antibodies by enzyme linked immunosorbance assay (ELISA). Plaque reduction neutralization test (PRNT), specific for dengue viruses, showed that 171 of these 184 flavivirus antibody positive sera had a neutralization titer against one or more DENV serotypes. A majority of the sera (62%) had neutralizing antibody to all four dengue serotypes. Only 26 PRNT positive sera (15%) had monotypic dengue virus neutralizing antibody, most of which (20 of 26) were against DENV2. Evidence of infection with all four serotypes was observed across all age groups except in the youngest age group (10–19 years) which contained only DENV2 positive individuals. In a multiple logistic regression model, only the length of residence on the island was a predictor of a positive dengue PRNT50 result. To our knowledge this is the first dengue serosurveillance study conducted on Sint Eustatius since the 1970s. The lack of antibodies to the DEN1, 3, and 4 in the samples collected from participants under 20 years of age suggests that only DEN2 has circulated on island since the early 1990s. The high prevalence of antibodies against dengue (83.8%) and the observation that the length of time on the island was the strongest predictor of infection suggests dengue is endemic on Sint Eustatius and a public health concern that warrants further investigation. [ABSTRACT FROM AUTHOR]

The development of a safe and effective vaccine to protect against COVID-19 is a global priority due to the current high SARS-CoV-2 infection rate. Currently, there are over 160 SARS-CoV-2 vaccine candidates at the clinical or pre-clinical stages of development. Of these, there are only three whole-virus vaccine candidates produced using β-propiolactone or formalin inactivation. Here, we prepared a whole-virus SARS-CoV-2 vaccine (SARS-CoV-2 PsIV) using a novel psoralen inactivation method and evaluated its immunogenicity in mice using two different adjuvants, alum and Advax-2. We compared the immunogenicity of SARS-CoV-2 PsIV against SARS-CoV-2 DNA vaccines expressing either full-length or truncated spike proteins. We also compared the psoralen-inactivated vaccine against a DNA prime, psoralen-inactivated vaccine boost regimen. After two doses, the psoralen-inactivated vaccine, when administered with alum or Advax-2 adjuvants, generated a dose-dependent neutralizing antibody responses in mice. Overall, the pattern of cytokine ELISPOT responses to antigen-stimulation observed in this study indicates that SARS-CoV-2 PsIV with the alum adjuvant promotes a Th2-type response, while SARS-CoV-2 PsIV with the Advax-2 adjuvant promotes a Th1-type response. [ABSTRACT FROM AUTHOR]

Background The WHO estimates that there may be 50 million cases of dengue virus (DENV) infection worldwide every year. There is no safe vaccine against DENV licensed in the United States. The development of a balanced and effective anti-DENV vaccine is vital to preventing morbidity and mortality. Codagenix used its proprietary SAVE (Synthetic Attenuated Virus Engineering) platform to generate and test a live attenuated, tetravalent vaccine against DENV. Methods Codagenix used SAVE to substitute under-represented human codons and codon-pairs into the E protein sequences of contemporary strains of DENV1-4, producing either a fully human-cell-deoptimized prM-E (E-Min), or a partially deoptimized prM-E (E-W/Min) to allow for balancing of the vaccine's immunogenicity. Full genomes containing deoptimized E-Min and E-W/Min in the DENV2 backbone were transfected into cells to recover live-attenuated, human-cell-deoptimized vaccine strains. Mice were vaccinated with 106 FFU of each DENV vaccine (alone or together), boosted on day 21 and assessed for neutralizing antibodies by PRNT50 and survival after lethal challenge with mouse-adapted wild-type (WT) DENV. Cynomolgus macaques were immunized with a mixture of 106 FFU of each DENV vaccine strain. Two doses were administered on study day 1 and 57 and serum neutralizing antibodies were determined on day 57 and 85 by a microneutralization assay. Results SAVE deoptimized DENV viruses grew to wild-type (between 107 and 108 FFU/ml) levels at permissive temperatures (<37C). All vaccine strains generated neutralizing antibody levels comparable to WT. A tetravalent formulation containing all four E-Min strains protected mice from lethal challenge with DENV3. A tetravalent formulation of Codagenix DENV-E-W/Min vaccine elicited a robust and balanced neutralizing antibody response in non-human primates (NHPs) against all four DENV serotypes after a single dose. A second vaccine dose did not boost antibody titers significantly. Conclusion The ability to rationally balance the attenuation of multiple vaccine strains, thereby avoiding antibody-dependent enhancement, is a unique advantage of the Codagenix SAVE platform. Codagenix DENV vaccine viruses generated balanced, sterilizing immunity in NHPs after one dose. Disclosures All authors: No reported disclosures. [ABSTRACT FROM AUTHOR]

Background: The hemagglutination-inhibition (HAI) assay is a critical component for measurement of immunogenicity in influenza vaccine development. It is unknown if the results can be influenced by sample type and anticoagulants. The purpose of this study was to evaluate the influence of different sample collection methods, in particular different anticoagulants, and choice of plasma or serum, on influenza virus serological assays.Methods: Blood samples from thirty donors previously immunized against influenza viruses were collected using six different types of blood collection tubes, two of which collect serum and four of which contain various anticoagulants for collecting plasma. Serum: (1) serum separator tubes (SST); and (2) Plus Plastic serum "red-top serum" tubes. Plasma: (3) spray-coated K2 ethylenediaminetetraacetic acid (EDTA) tubes: (4) Sodium Heparin tubes; (5) Citrate tubes with 3.2% sodium citrate solution; and (6) Glass Blood Collection tubes with acid citrate dextrose. Samples were tested against three different influenza viruses (A/California/07/2009 (H1N1pdm09), A/Texas/50/2012 (H3N2), and B/Massachusetts/2/2012) for hemagglutination inhibition titer and virus neutralization titer via a microneutralization (MN) assay, and data compared to that obtained for standard serum sample collected in SST.Results: HAI and MN titers against type A viruses were within two dilutions compared to SST collection method over 96% of the time irrespective of sample type or anticoagulant. However, HAI titers for type B virus were more variable across different collection methods. EDTA plasma samples were greater than two dilutions higher than SST serum samples 70% (21 of 30 samples) of the time. In contrast, MN titers were within two dilutions over 96% of the time, with the highest deviation noted in acid citrate dextrose plasma samples (3 of 30 samples tested, 10%).Conclusions: These data provide useful guidelines for sample collection and serology testing when screening: (i) influenza vaccine immunogenicity antibody response; (ii) antibody responses to newly emerging viral strains; and (iii) clinical samples for anti-influenza antibody activity. [ABSTRACT FROM AUTHOR]