Rabies Virus Neutralizing Activity,Safety,and Immunogenicity of Recombinant Human Rabies Antibody Compared with Human Rabies Immunoglobulin in Healthy Adults

Objective Preliminary assessment of rabies virus neutralizing activity,safety and immunogenicity of a recombinant human rabies antibody(NM57)compared with human rabies immunoglobulin(HRIG)in Chinese healthy adults.Methods Subjects were randomly(1:1:1)allocated to Groups A(20 IU/kg NM57),B(40 IU/kg NM57),or C(20 IU/kg HRIG).One injection was given on the day of enrollment.Blood samples were collected on days-7 to 0(pre-injection),3,7,14,28,and 42.Adverse events(AEs)and serious AEs(SAEs)were recorded over a period of 42 days after injection.Results All 60 subjects developed detectable rabies virus neutralizing antibodies(RVNAs)(>0.05 IU/mL)on days 3,7,14,28,and 42.The RVNA levels peaked on day 3 in all three groups,with a geometric mean concentration(GMC)of 0.2139 IU/mL in Group A,0.3660 IU/mL in Group B,and0.1994 IU/mL in Group C.At each follow-up point,the GMC in Group B was significantly higher than that in Groups A and C.The areas under the antibody concentration curve over 0-14 days and 0-42 days in Group B were significantly larger than those in Groups A and C.Fifteen AEs were reported.Except for one grade 2 myalgia in Group C,the other 14 were all grade 1.No SAEs were observed.Conclusion The rabies virus neutralizing activity of 40 IU/kg NM57 was superior to that of 20 IU/kg NM57 and 20 IU/kg HRIG,and the rabies virus neutralizing activity of 20 IU/kg NM57 and 20 IU/kg HRIG were similar.Safety was comparable between NM57 and HRIG.

Murine antibody against E2 can capture hepatitis C virus in vitro

Objective To find neutralizing antibody candidates against hepatitis C virus (HCV) infection.Methods We constructed two eukaryotic expression vectors which contained the E1 and E2 gene of HCV, and detected their expression in mammalian cells with transient expression. BALB/c mice were given subculaneous injections of constructed vectors combined with the IL-2 gene intraepidermally and evaluated for induced humoral immune responses by enzyme-linked immunosorbent assay (ELISA). We used an antibody-virus interaction assay to analyze the interaction of the antisera and HCV viral particles in vitro.Results Anti E1 and anti-E2 antisera were obtained from immunized mice. The serum of mice immunized with the E2 gene immunoprecipitated the HCV isolate in source serum and reacted with the isolates unrelated to the original one.Conclusions Anti-E2 antibody in induced mice can cross-reactively capture HCV particles, highlighting the possibility of generating broadly reactive anti-E2 antibodies.

Pathogenicity of an FAdV-4 isolate to chickens and its genomic analysis

Fowl adenovirus serotype 4(FAdV-4)strain SD1511 was isolated from chickens with severe inclusion body hepatitis and hydropericardium syndrome in Shandong Province,China.The isolate was cultured in primary chicken embryo kidney cells.A study of pathogenicity indicated that SD1511 readily infected 7–35-d-old chickens by intramuscular injection and intranasal and oral routes,causing 50%–100%mortality.The 35-d-old chickens suffered more severe infection than 7-and 21-d-old chickens with mortality highest in the intramuscular injection group.The serum from surviving chickens showed potent viral neutralizing capability.The complete genome of SD1511 was sequenced and analyzed.The strain was found to belong to the FAdV-4 cluster with more than 99%identity with the virulent FAdV-4 strains isolated in China in recent years except for some distinct variations,including deletions of open reading frame 27(ORF27),ORF48,and part of ORF19.Our findings suggest that SD1511 might be used as a prototype strain for the study of pathogenesis and vaccine development.

Detecting SARS-CoV-2 neutralizing immunity: highlighting the potential of split nanoluciferase technology

The coronavirus disease 2019(covID-19)pandemic has progressed over 2 years since its onset causing significant health concerns all over the world and is currently curtailed by mass vaccination.mmunity acquired against severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)can be following either infection or vaccination.However,one can never be sure whether the acquired immunity is adequate to protect the individual from subsequent infection because of three important factors:individual variations in humoral response dynamics,waning of protective antibodies over time,and the emergence of immune escape mutants.Therefore,a test that can accurately dfferentiate the protected from the vulnerable is the need of the hour.The plaque reduction neutralization assay is the conventional gold standard test for estimating the titers of neutralizing antibodies that confer protection.However,it has got several drawbacks,which hinder the practical application of this test for wide-scale usage.Hence,various tests have been developed to detect protective immunity against SARS-CoV-2 that directly or indirectly assess the presence of neutralizing antibodies to SARS-Cov-2 in a lower biosafety setting.In this review,the pros and cons of the currently available assays are elaborated in detail and special focus is put on the scope of the novel split nanoluciferase technology for detecting SARS-CovV-2 neutralizing antibodies.