Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 6 de 6
Filter
1.
iScience ; : 105696, 2022 Nov 30.
Article in English | MEDLINE | ID: covidwho-2238787

ABSTRACT

The severe acute respiratory syndrome spread worldwide, causing a pandemic. SARS-CoV-2 mutations have arisen in the spike, a glycoprotein at the viral envelope and an antigenic candidate for vaccines against COVID-19. Here, we present comparative data of the glycosylated full-length ancestral and D614G spike together with three other transmissible strains classified by the World Health Organization as variants of concern: beta, gamma, and delta. By showing that D614G has less hydrophobic surface exposure and trimer persistence, we place D614G with features that support a model of temporary fitness advantage for virus spillover. Further, during the SARS-CoV-2 adaptation, the spike accumulates alterations leading to less structural stability for some variants. The decreased trimer stability of the ancestral and gamma and the presence of D614G uncoupled conformations mean higher ACE-2 affinities compared to the beta and delta strains. Mapping the energetics and flexibility of variants is necessary to improve vaccine development.

2.
Front Immunol ; 13: 918896, 2022.
Article in English | MEDLINE | ID: covidwho-2198845

ABSTRACT

Background: Effective and safe vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are critical to controlling the COVID-19 pandemic and will remain the most important tool in limiting the spread of the virus long after the pandemic is over. Methods: We bring pioneering contributions on the maintenance of the immune response over a year on a real-life basis study in 1,587 individuals (18-90 yrs, median 39 yrs; 1,208 female/379 male) who underwent vaccination with two doses of CoronaVac and BNT162b2 booster after 6-months of primary protocol. Findings: Elevated levels of anti-spike IgG antibodies were detected after CoronaVac vaccination, which significantly decreased after 80 days and remained stable until the introduction of the booster dose. Heterologous booster restored antibody titers up to-1·7-fold, changing overall seropositivity to 96%. Titers of neutralising antibodies to the Omicron variant were lower in all timepoints than those against Delta variant. Individuals presenting neutralising antibodies against Omicron also presented the highest titers against Delta and anti-Spike IgG. Cellular immune response measurement pointed out a mixed immune profile with a robust release of chemokines, cytokines, and growth factors on the first month after CoronaVac vaccination followed by a gradual reduction over time and no increase after the booster dose. A stronger interaction between those mediators was noted over time. Prior exposure to the virus leaded to a more robust cellular immune response and a rise in antibody levels 60 days post CoronaVac than in individuals with no previous COVID-19. Both vaccines were safe and well tolerated among individuals. Interpretation: Our data approach the effectiveness of CoronaVac association with BNT162b2 from the clinical and biological perspectives, aspects that have important implications for informing decisions about vaccine boosters. Funding: Fiocruz, Brazil.


Subject(s)
COVID-19 Vaccines , COVID-19 , Immunization, Secondary , Immunogenicity, Vaccine , Antibodies, Neutralizing , Antibodies, Viral , BNT162 Vaccine/immunology , Brazil , COVID-19/prevention & control , COVID-19 Vaccines/adverse effects , COVID-19 Vaccines/immunology , Female , Follow-Up Studies , Humans , Immunoglobulin G , Male , Pandemics , SARS-CoV-2
3.
Vaccines (Basel) ; 10(8)2022 Aug 12.
Article in English | MEDLINE | ID: covidwho-1988051

ABSTRACT

Despite the intramuscular route being the most used vaccination strategy against SARS-CoV-2, the intradermal route has been studied around the globe as a strong candidate for immunization against SARS-CoV-2. Adjuvants have shown to be essential vaccine components that are capable of driving robust immune responses and increasing the vaccination efficacy. In this work, our group aimed to develop a vaccination strategy for SARS-CoV-2 using a trimeric spike protein, by testing the best route with formulations containing the adjuvants AddaS03, CpG, MPL, Alum, or a combination of two of them. Our results showed that formulations that were made with AddaS03 or CpG alone or AddaS03 combined with CpG were able to induce high levels of IgG, IgG1, and IgG2a; high titers of neutralizing antibodies against SARS-CoV-2 original strain; and also induced high hypersensitivity during the challenge with Spike protein and a high level of IFN-γ producing CD4+ T-cells in mice. Altogether, those data indicate that AddaS03, CpG, or both combined may be used as adjuvants in vaccines for COVID-19.

5.
Biochem Eng J ; 186: 108537, 2022 Aug.
Article in English | MEDLINE | ID: covidwho-1936085

ABSTRACT

Serological tests detect antibodies generated by infection or vaccination, and are indispensable tools along different phases of a pandemic, from early monitoring of pathogen spread up to seroepidemiological studies supporting immunization policies. This work discusses the development of an accurate and affordable COVID-19 antibody test, from production of a recombinant protein antigen up to test validation and economic analysis. We first developed a cost-effective, scalable technology to produce SARS-COV-2 spike protein and then used this antigen to develop an enzyme-linked immunosorbent assay (ELISA). A receiver operator characteristic (ROC) analysis allowed optimizing the cut-off and confirmed the high accuracy of the test: 98.6% specificity and 95% sensitivity for 11+ days after symptoms onset. We further showed that dried blood spots collected by finger pricking on simple test strips could replace conventional plasma/serum samples. A cost estimate was performed and revealed a final retail price in the range of one US dollar, reflecting the low cost of the ELISA test platform and the elimination of the need for venous blood sampling and refrigerated sample handling in clinical laboratories. The presented workflow can be completed in 4 months from first antigen expression to final test validation. It can be applied to other pathogens and in future pandemics, facilitating reliable and affordable seroepidemiological surveillance also in remote areas and in low-income countries.

6.
iScience ; 24(11): 103315, 2021 Nov 19.
Article in English | MEDLINE | ID: covidwho-1474644

ABSTRACT

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 1:106, and the neutralizing antibody titer against authentic virus (WT) was 1:14,604 (average PRNT90). Plasma from immunized animals was pepsin digested to remove the Fc portion and purified, yielding an F(ab')2 preparation with PRNT90 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 the WT and P.2 variants, but displaced to higher concentrations by 0.39 log units against the P.1 (Gamma) variant. These results support the possibility of using equine F(ab')2 preparation for the clinical treatment of COVID patients.

SELECTION OF CITATIONS
SEARCH DETAIL