ABSTRACT
SARS-CoV-2 variants of concern (VOCs), especially the latest Omicron, have exhibited severe antibody evasion. Broadly neutralizing antibodies with high potency against Omicron are urgently needed for understanding working mechanisms and developing therapeutic agents. In this study, we characterized previously reported F61, which was isolated from convalescent patients infected with prototype SARS-CoV-2, as a broadly neutralizing antibody against all VOCs including Omicron BA.1, BA.1.1, BA.2, BA.3 and BA.4 sublineages by utilizing antigen binding and cell infection assays. We also identified and characterized another broadly neutralizing antibody D2 with epitope distinct from that of F61. More importantly, we showed that a combination of F61 with D2 exhibited synergy in neutralization and protecting mice from SARS-CoV-2 Delta and Omicron BA.1 variants. Cryo-EM structures of the spike-F61 and spike-D2 binary complexes revealed the distinct epitopes of F61 and D2 at atomic level and the structural basis for neutralization. Cryo-EM structure of the Omicron-spike-F61-D2 ternary complex provides further structural insights into the synergy between F61 and D2. These results collectively indicated F61 and F61-D2 cocktail as promising therapeutic antibodies for combating SARS-CoV-2 variants including diverse Omicron sublineages.
ABSTRACT
SARS-CoV-2 continued to spread globally along with different variants. Here, we systemically analyzed viral infectivity and immune-resistance of SARS-CoV-2 variants to explore the underlying rationale of viral mutagenesis. We found that the Beta variant harbors both high infectivity and strong immune resistance, while the Delta variant is the most infectious with only a mild immune-escape ability. Remarkably, the Omicron variant is even more immune-resistant than the Beta variant, but its infectivity increases only in Vero E6 cells implying a probable preference for the endocytic pathway. A comprehensive analysis revealed that SARS-CoV-2 spike protein evolved into distinct evolutionary paths of either high infectivity plus low immune resistance or low infectivity plus high immune resistance, resulting in a narrow spectrum of the current single-strain vaccine. In light of these findings and the phylogenetic analysis of 2674 SARS-CoV-2 S-protein sequences, we generated a consensus antigen (S6) taking the most frequent mutations as a pan-vaccine against heterogeneous variants. As compared to the ancestry SWT vaccine with significantly declined neutralizations to emerging variants, the S6 vaccine elicits broadly neutralizing antibodies and full protections to a wide range of variants. Our work highlights the importance and feasibility of a universal vaccine strategy to fight against antigen drift of SARS-CoV-2.
ABSTRACT
OBJECTIVE To evaluate the long-term toxicity of fully human anti-human tumor necrosis factor-α monoclonal antibody(anti-hTNF-α FHMA)for injection in cynomolgus monkeys. METHODS Forty cynomolgus monkeys were randomly divided into 5 groups (4 males and 4 females in each group):negative control group,adalimumab 10 mg·kg-1 group,anti-hTNF-αFHMA 2,10 and 50 mg·kg-1 groups. Cynomolgus monkeys in each group were injected sc once a week for 5 consecutive times, followed by 4 weeks of recovery. During the test,general clinical observation,body mass,body temperature,electrocardiogram(ECG),hematology,coagulation function,blood biochemistry,urine, ophthalmology,immune index,and pathological changes in organs and tissues were observed. At the same time,plasma drug concentrations were detected and the toxicokinetics parameters were analyzed. RESULTS No significant toxicological changes related to drugs were observed in general clinical observation,body mass,body temperature,ECG,ophthalmic examination,blood cell counts,coagu?lation function,blood biochemistry,urine analysis,lymphocyte subsets,cytokines,serum immuno?globulin,serum complement. Neutralizing anti-drug antibody(ADA)could be detected in adalimumab group and anti-hTNF-αFHMA groups. Anti-hTNF-αFHMA showed linear dynamic characteristics in cyno?molgus monkeys. At the same dose(10 mg·kg-1),anti-hTNF-αFHMA had similar immunogenicity and kinetics characteristics to adalimumab. CONCLUSION The level of anti-hTNF-α FHMA at which no adverse effect was observed was 50 mg · kg-1,which is equivalent to 75 times clinical dosage of quasi (0.67 mg·kg-1),which suggests that anti-hTNF-αFHMA be safe in clinical use.
