Prokaryotic Expression and Immunogenicity of Dominant Epitope Region of Goose Parvovirus Structural Protein VP3

[Objective] The paper was to develop a subunit vaccine candidate for prevention and control of goose parvovirus infection. [Method]Based on the prokaryotic expression system, the antigenic epitopes and locations of the structural protein VP3 were predicted by software analysis,and the region displaying a large portion of antigenic epitopes was amplified by PCR. The target VP3 DNA fragment was inserted into pET-30 a-VP3 vector, was transformed into Escherichia coli BL21 competent cells for protein expression and animal test. The SPF chickens were immunized with the recombinant protein and the antisera were collected for neutralization test by using a goose embryo fibroblast. [Result] The recombinant plasmid was constructed, and the target region of VP3 protein was expressed efficiently in a soluble form. The neutralizing titers of antisera could reach up to-2.608. [Conclusion] The target region displaying a large portion of antigenic epitopes of the structural protein VP3 could be expressed efficiently in soluble form, and the expressed protein could induce neutralizing antibodies in SFP chicken.

Utility of convalescent plasma for addressing the COVID-19 infection: brief review and case reports

Novel coronavirus,SARS-CoV-2 is responsible for causing a pandemic that has affected individuals worldwide,over 192 million people and about 4.1 million people died so far.The spread is ongoing and the numbers are still increasing.Numerous therapeutic approaches have been explored and developed during this pandemic.Immunotherapy with virus-specific antibodies in convalescent plasma(CP)has shown potential benefits for various pathogenic diseases.In many instances,it is the only available and safe management option for the COVID-19 patients.Here we describe two confirmed cases of COVID-19 from two different geographical areas that were managed with standard treatment modalities initially.Both of the patients were presented with high-grade fever,dry cough,and sore throat.Lab reports showed increased values of D-dimer,serum ferritin,leukocyte count(LC),Lactate dehydrogenase(LDH),and C-reactive protein(CRP).Chest X-ray showed bilateral infiltration(multifocal and bilateral ground-glass opacities and consolidations with peripheral and basal predominance),consistent with the previous reports on COVID-19 infection.The patients received conservative treatment according to the hospital's protocol.The convalescent plasma(from recovered patients)infusion was the last treatment given to both patients.After the convalescent plasma transfusion,both patients showed a reduction of viral load,an increase of anti-SARS-CoV-2 IgG and IgM antibodies,reduction in lung infiltration,with no adverse events.However,further randomized controlled trials are needed to investigate the full scope of safety and efficacy(both short and long-term)of convalescent plasma therapy for COVID-19 and other related infections.

SARS-CoV-2 spike RBD-specific IgA and IgG antibodies in breast milk after vaccination with the protein subunit vaccine Abdala

Background:COVID-19 vaccines that trigger a strong secretory antibody response in breast milk may achieve effective passive protection of vulnerable newborns and breastfed infants of immunized mothers.The aim of this work was to investigate the presence of SARS-CoV-2 spike RBD-specific IgA and IgG antibodies in breast milk,5 and 9 weeks after vaccination with 3 doses of the protein subunit vaccine Abdala,compared to those found in breast milk from COVID-19-recovered women,collected at least 40 days after the infection.Methods:SARS-CoV-2 spike RBD-specific IgA and IgG antibodies were semi-quantified by indirect ELISA,using a homemade standard generated by pooling twenty breast milk samples with high absorbance values according to preliminary data.The validity of the standard curves was proved following the European Medicines Agency Guideline.Two breast milk samples from 2 unvaccinated women who had not been infected with COVID-19 were included as negative controls.Potentially neutralizing antibodies was assessed by a SARS-CoV-2 surrogate virus neutralization test.Results:High levels of anti-RBD IgA antibodies were detected in breast milk samples 9 weeks after vaccination and anti-RBD IgG antibodies rise from the fifth to the ninth week.In the post-COVID-19 time that was evaluated,the IgG-type response was notably higher compared to both post-vaccination periods.Neutralizing antibody titers were similar in breast milk from vaccinated and COVID-19 recovered women.Conclusions:This is the first report about the immune response in breast milk after the administration of a COVID-19 protein subunit vaccine,which could provide analogous protection to that conferred by SARS-CoV-2 infection.This implies a potential passive immunity that breastfed infants receive from their mothers vaccinated with Abdala.