Biology subjects

Urbanowicz, R. A.

Publications and source records attributed to Urbanowicz, R. A..

3 recordsLinked to original sources

bioRxiv2021

A novel bivalent DNA vaccine encoding both spike protein receptor-binding domain and nucleocapsid protein of SARS-CoV-2 to elicit T cell and neutralising antibody responses that cross react with variants

Although the efficacy of vaccines targeting SARS-CoV-2 is apparent now that the approved mRNA and adenovirus vector vaccines are in widespread use, the longevity of the protective immune response and its efficacy against emerging variants remains to be determined. We have therefore designed a DNA vaccine encoding both the SARS-CoV-2 spike receptorbinding domain ( RBD) and nucleocapsid proteins, the latter of which is highly conserved amongst beta coronaviruses. The vaccine elicits strong pro-inflammatory CD4+ Th1 and CD8+ T-cell responses to both proteins in mice and rats, with responses being significantly enhanced by fusing the nucleocapsid sequence to a modified Fc domain. We have shown that the vaccine also stimulates high titre antibody responses to RBD in mice that efficiently neutralise in pseudotype and live virus neutralisation assays and show cross reactivity with spike proteins from the variants B.1.1.7 (Alpha), B.1.351 (Beta) and B.1.617.2 (Delta). The vaccine also showed good protection in a viral challenge model in ACE2 receptor transgenic mice. This DNA platform can be easily adapted to target variant proteins and we show that a vaccine variant encoding the Beta variant sequence stimulates cross-reactive humoral and T cell responses. These data support the translation of this DNA vaccine platform into the clinic, thereby offering a particular advantage for rapidly targeting emerging SARS-CoV-2 variants.

immunology↗

bioRxiv2020

Immunogenicity of a new gorilla adenovirus vaccine candidate for COVID-19

The COVID-19 pandemic caused by the emergent SARS-CoV-2 coronavirus threatens global public health and there is an urgent need to develop safe and effective vaccines. Here we report the generation and the preclinical evaluation of a novel replication-defective gorilla adenovirus-vectored vaccine encoding the pre-fusion stabilized Spike (S) protein of SARS-CoV2. We show that our vaccine candidate, GRAd- COV2, is highly immunogenic both in mice and macaques, eliciting both functional antibodies which neutralize SARS-CoV-2 infection and block Spike protein binding to the ACE2 receptor, and a robust, Th1- dominated cellular response in the periphery and in the lung. We show here that the pre-fusion stabilized Spike antigen is superior to the wild type in inducing ACE2-interfering, SARS-CoV2 neutralizing antibodies. To face the unprecedented need for vaccine manufacturing at massive scale, different GRAd genome deletions were compared to select the vector backbone showing the highest productivity in stirred tank bioreactors. This preliminary dataset identified GRAd-COV2 as a potential COVID-19 vaccine candidate, supporting the translation of GRAd-COV2 vaccine in a currently ongoing Phase I clinical trial (NCT04528641).

immunology↗

bioRxiv2020

Structure-based design of hepatitis C virus E2 glycoprotein improves serum binding and cross-neutralization

An effective vaccine for hepatitis C virus (HCV) is a major unmet need, and it requires an antigen that elicits immune responses to key conserved epitopes. Based on structures of antibodies targeting HCV envelope glycoprotein E2, we designed immunogens to modulate the structure and dynamics of E2 and favor induction of bNAbs in the context of a vaccine. These designs include a point mutation in a key conserved antigenic site to stabilize its conformation, as well as redesigns of an immunogenic region to add a new N-glycosylation site and mask it from antibody binding. Designs were experimentally characterized for binding to a panel of human monoclonal antibodies (HMAbs) and the coreceptor CD81 to confirm preservation of epitope structure and preferred antigenicity profile. Selected E2 designs were tested for immunogenicity in mice, with and without hypervariable region 1, which is an immunogenic region associated with viral escape. One of these designs showed improvement in polyclonal immune serum binding to HCV pseudoparticles and neutralization of isolates associated with antibody resistance. These results indicate that antigen optimization through structure-based design of the envelope glycoproteins is a promising route to an effective vaccine for HCV.

microbiology↗