Venzon, D. J. | bioRxiv Science

bioRxiv2021

Control of SARS-CoV-2 infection after Spike DNA or Spike DNA+Proteinco-immunization in rhesus macaques

The speed of development, versatility and efficacy of mRNA-based vaccines have been amply demonstrated in the case of SARS-CoV-2. DNA vaccines represent an important alternative since they induce both humoral and cellular immune responses in animal models and in human trials. We tested the immunogenicity and protective efficacy of DNA-based vaccine regimens expressing different prefusion-stabilized SARS-CoV-2 Spike antigens upon intramuscular injection followed by electroporation in rhesus macaques. Different Spike DNA vaccine regimens induced antibodies that potently neutralized SARS-CoV-2 in vitro and elicited robust T cell responses. The DNA-only vaccine regimens were compared to a regimen that included co- immunization of Spike DNA and protein in the same anatomical site, the latter of which showed significant higher antibody responses. All vaccine regimens led to control of SARS-CoV-2 intranasal/intratracheal challenge and absence of virus dissemination to the lower respiratory tract. Vaccine-induced binding and neutralizing antibody titers and antibody-dependent cellular phagocytosis inversely correlated with transient virus levels in the nasal mucosa. Importantly, the Spike DNA+Protein co-immunization regimen induced the highest binding and neutralizing antibodies and showed the strongest control against SARS-CoV-2 challenge in rhesus macaques. Author summaryAnti-Spike neutralizing antibodies provide strong protection against SARS-CoV-2 infection in animal models, and correlate with protection in humans, supporting the notion that induction of strong humoral immunity is key to protection. We show induction of robust antibody and T cell responses by different Spike DNA-based vaccine regimens able to effectively mediate protection and to control SARS-CoV-2 infection in the rhesus macaque model. This study provides the opportunity to compare vaccines able to induce different humoral and cellular immune responses in an effort to develop durable immunity against the SARS-CoV-2. A vaccine regimen comprising simultaneous co-immunization of DNA and Protein at the same anatomical site showed best neutralizing abilities and was more effective than DNA alone in inducing protective immune responses and controlling SARS-CoV-2 infection. Thus, an expansion of the DNA vaccine regimen to include co-immunization with Spike protein may be of advantage also for SARS-CoV-2.

immunology↗

bioRxiv2020

Iterative Epigenomic Analyses in the Same Single Cell

Gene expression in individual cells is epigenetically regulated by DNA modifications, histone modifications, transcription factors and other DNA-binding proteins. It has been shown that multiple histone modifications can predict gene expression and reflect future responses of bulk cells to extracellular cues. However, the predictive ability of epigenomic analysis is still limited for mechanistic research at a single cell level. To overcome this limitation, it is useful to acquire reliable signals from multiple epigenetic marks in the same single cell. Here, we propose a new approach for analysis of several components of the epigenome in the same single cell. The new method allows reanalysis of the same single cell. We found that reanalysis of the same single cell is feasible, and provides confirmation of the signals and allows application of statistical analysis to identify reliable signals using data sets generated only from the single cell. Reanalysis of the same single cell is also useful to acquire multiple-epigenetic marks from the same single cells. The method can acquire at least 4 epigenetic marks, H3K27ac, H3K27me3, mediator complex subunit 1 and a DNA modification. We predicted active signaling pathways in K562 single cells using the data. We confirmed that the prediction results showed a strong correlation with actual active signaling pathways shown by RNA-seq results. These results suggest that the new approach provides mechanistic insights for cellular phenotypes through multi-layered epigenome analysis in the same single cells.

genomics↗