Chimeric mRNA based COVID-19 vaccine elicits potent neutralizing antibodies and protection against Omicron and Delta

The emerging SARS-CoV-2 variants of concern (VOCs) exhibit enhanced transmission and immune escape, reducing the efficacy and effectiveness of the two FDA-approved mRNA vaccines. Here, we explored various strategies to develop novel mRNAs vaccines to achieve safer and wider coverage of VOCs. Firstly, we constructed a cohort of mRNAs that feature a furin cleavage mutation in the spike (S) protein of predominant VOCs, including Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1) and Delta (B.1.617.2). Not present in the mRNA vaccines currently in use, the mutation abolished the cleavage between the S1 and S2 subunits, potentially enhancing the safety profile of the immunogen. Secondly, we systematically evaluated the induction of neutralizing antibodies (nAb) in vaccinated mice, and discovered that individual VOC mRNAs elicited strong neutralizing activity in a VOC-specific manner. Thirdly, the IgG produced in mice immunized with Beta-Furin and Washington (WA)-Furin mRNAs showed potent cross-reactivity with other VOCs, which was further corroborated by challenging vaccinated mice with the live virus of VOCs. However, neither WA-Furin nor Beta-Furin mRNA elicited strong neutralizing activity against the Omicron variant. Hence, we further developed an Omicron-specific mRNA vaccine that restored protection against the original and the sublineages of Omicron variant. Finally, to broaden the protection spectrum of the new Omicron mRNA vaccine, we tested the concept of bivalent immunogen. Instead of just fusing two RBDs head-to-tail, we for the first time constructed an mRNA-based chimeric immunogen by introducing the RBD of Delta variant into the entire S antigen of Omicron. The resultant chimeric mRNA was capable of inducing potent and broadly acting nAb against Omicron (both BA.1 and BA.2) and Delta, which paves the way to develop new vaccine candidate to target emerging variants in the future.

Directing an mRNA-LNP vaccine toward lymph nodes improves humoral and cellular immunity against SARS-CoV-2

The exploration and identification of safe and effective vaccines for the SARS-CoV-2 pandemic has captured the worlds attention and remains an ongoing issue in order to protect against emerging variants of concern (VoCs) while generating long lasting immunity. Here, we report the synthesis of a novel messenger ribonucleic acid (mRNA) encoding the spike protein in a lipid nanoparticle formulation (LNP) (STI-7264) that generates robust humoral and cellular immunity following immunization of C57Bl6 mice. In efforts to continually improve immunity, a lymphatic drug delivery device (MuVaxx) was engineered and tested to modulate immune cells at the injection site (epidermis and dermis) and draining lymph node (LN) to elicit adaptive immunity. Using MuVaxx, immune responses were elicited and maintained at a 10-fold dose reduction compared to traditional intramuscular (IM) administration as measured by anti-spike antibodies, cytokine producing CD8 T cells, and neutralizing antibodies against the Washington (Wild Type, WT) and South African (beta) variants. Remarkably, a 4-fold elevated T cell response was observed in MuVaxx administered vaccination as compared to that of IM administered vaccination. Thus, these data support further investigation into STI-7264 and lymphatic mediated delivery using MuVaxx for SARS-CoV-2 and VoCs vaccines.

Preparation and characterization of monoclonal antibody against hTSC29 pep-tides / 中国免疫学杂志

Objective:To prepare monoclonal antibody ( mAb ) against human testis-specific conserved gene ( hTSC29 ) peptides and characterize its immunological and biological features.Methods:According to bioinformatics analysis and prediction of the antigenicity, surface property, hydrophilicity and flexibility of hTSC29, a 18-amino acid residue partial peptide of hTSC29 was synthesized,then immunized the BALB/c mice for preparing antiserum.The mAb against hTSC29 was produced using the routine hybridoma technique.The properties of the mAb against hTSC29 were identified by ELISA, Western blot and immunohistochemistry staining.Results:After cell fusion and subcloning, one hybridoma cell lines secreting specific mAb against hTSC29 protein were obtaind.The Ig subclass of the mAb was IgG2b(κ).ELISA detection showed that the titer of mAbs in cultured was 1∶104.Western blot analysis proved that the mAb could specifically recognize Mr 60 000 protein in human testis total protein.The hTSC29 protein main located at circumference of spermatocyte and spermatid in human testis tissue by immunohistochemistry staining and immunofluorescence assay.Conclusion:One hybridoma cell lines which can secrete specific mAb against hTSC29 protein with high titers and specificity have been established successfully.The mAb will provide efficient tools for functional studies of hTSC29 expressed in spermatogenesis.

The relationship between the semen quality and age in infertile men in Qingyuan / 国际检验医学杂志

Objective To study the relationship between the semen quality and age in infertile men in Qingyuan.Methods 727 cases of infertile men from Reproductive Medicine Center outpatient were enrolled and divided into 5 groups:≤ 25,> 25 - 30,>30-35,>35-40,>40 age groups.The semen characteristics were carried out by calculator assistance sperm analysis(CASA) technique and Diff-Quick staining method.Results The sperm density of >30 -35 age group was the highest,but there was no significantly difference from other groups(P >0.05).Semen analysis showed that the rates of PR,PR+NP and survival sperm were on downward trends with the increase of age,but not statistically significant(P >0.05).38.19% of >25 -30 age group reached WHO′s semen parameters standard,which was the highest proportion among 5 groups.And the proportion in >40 age group was the lowest,which counted for 27.42%.Conclusion The semen quality shows a down trend with the increase of age,however,the infertility could occur in the reproductive men at any stage.