We used the recombinant trimeric spike (S) glycoprotein in the prefusion conformation to immunize horses for the production of hyperimmune globulins against SARS-CoV-2. Serum antibody titers measured by ELISA were above 1:10 6 , and the neutralizing antibody titer against authentic virus (WT) was 1:14,604 (average PRNT 90 ). Plasma from immunized animals was pepsin digested to remove the Fc portion and purified, yielding an F(ab’) 2 preparation with PRNT 90 titers 150-fold higher than the neutralizing titers in human convalescent plasma. Challenge studies were carried out in hamsters and showed the in vivo ability of equine F(ab’) 2 to reduce viral load in the pulmonary tissues and significant clinical improvement determined by weight gain. The neutralization curve by F(ab’) 2 was similar against WT and P.2 variant but displaced to higher concentrations by 0.39 log units against P.1 (Gamma) variant. These results support the possibility of using equine F(ab’) 2 preparation for the clinical treatment of COVID patients.
COVID-19 pandemic caused approximately 750,000 deaths and over 20 million confirmed cases of infection by SARS-CoV-2 within 8 months since the emergence of the virus. While there are no vaccines approved and considering the difficulty in meeting the large vaccination demand worldwide, the potential use of passive immunization should be considered based on existing successful therapies against many diseases. Here we demonstrate that hyperimmune globulin preparations raised in horses against the recombinant trimeric spike (S) glycoprotein of SARS-CoV-2 in the prefusion conformation provide very high ELISA titers as well as highly potent neutralizing activity against SARS-CoV-2. Five horses were subcutaneously inoculated for 6 weeks with the recombinant S protein (ectodomain, residues 1-1208). Four out of the 5 horses presented a strong immune response. Considering the average of all 5 horses, ELISA titers above 1:1,000,000 and neutralizing titers (PRNT90) reaching 1:14,604 were observed. When compared with the plasma of three convalescent COVID-19 patients, sera of immunized horses displayed approximately 140-fold higher neutralizing titers measured as PRNT90. To prevent eventual side effects caused by horse antiserum, IgG was digested with pepsin and purified by fractional salt precipitation to eliminate Fc fragments, a process that is industrially used for the production of passive immunization F(ab')2 concentrates against rabies, tetanus and snake venoms. The high neutralizing titers against SARS-CoV-2 obtained for the unprocessed sera were confirmed for the F(ab')2 fragments and were 150-fold higher than the PRNT90 neutralizing titers of plasma of three COVID-19 convalescent patients. The great advantage of using the recombinant trimeric S glycoprotein is that it is safe and provides quick adaptive immunity in horses. Our data show the perspective of using hyperimmune anti-SARS-CoV-2 F(ab')2 preparations as a passive immunization therapy in humans, similar to therapies that have been safely used for decades against rabies, tetanus and snake venoms.
Monomelic amyotrophy (MA) is a rare condition in which neurogenic amyotrophy is restricted to an upper or lower limb. Usually sporadic, it usually has an insidious onset with a mean evolution of 2 to 4 years following first clinical manifestations, which is, in turned, followed by stabilization. We report a case of 20-years-old man who presented slowly progressive amyotrophy associated with proximal paresis of the right upper limb, which was followed by clinical stabilization 4 years later. Eletroneuromyography revealed denervation along with myofasciculations in various muscle groups of the right upper limb. We call attention to this rare location of MA, as well as describe some theories concerning its pathophysiology .
Whole inactivated vaccines (WIVs) possess greater immunogenicity than split or subunit vaccines, and recent studies have demonstrated that WIVs with preserved fusogenic activity are more protective than non-fusogenic WIVs. In this work, we describe the inactivation of human influenza virus X-31 by high hydrostatic pressure (HHP) and analyze the effects on the structure by spectroscopic measurements, light scattering, and electron microscopy. We also investigated the effects of HHP on the glycoprotein activity and fusogenic activity of the viral particles. The electron microscopy data showed pore formation on the viral envelope, but the general morphology was preserved, and small variations were seen in the particle structure. The activity of hemagglutinin (HA) during the process of binding and fusion was affected in a time-dependent manner, but neuraminidase (NA) activity was not affected. Infectious activity ceased after 3 hours of pressurization, and mice were protected from infection after being vaccinated. Our results revealed full viral inactivation with overall preservation of viral structure and maintenance of fusogenic activity, thereby conferring protection against infection. A strong response consisting of serum immunoglobulin IgG1, IgG2a, and serum and mucosal IgA was also detected after vaccination. Thus, our data strongly suggest that applying hydrostatic pressure may be an effective method for developing new vaccines against influenza A as well as other viruses.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.