Induction of Broadly Cross-Reactive Antibody Responses to SARS-CoV-2 Variants by S1 Nanoparticle Vaccines.

Despite the rapid deployment of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines, the emergence of SARS-CoV-2 variants and reports of their immune evasion characteristics have led to an urgent need for novel vaccines that confer potent cross-protective immunity. In this study, we constructed three different SARS-CoV-2 spike S1-conjugated nanoparticle vaccine candidates that exhibited high structural homogeneity and stability. Notably, these vaccines elicited up to 50-times-higher neutralizing antibody titers than the S1 monomer in mice.

Quadrivalent mosaic HexaPro-bearing nanoparticle vaccine protects against infection of SARS-CoV-2 variants.

Emerging SARS-CoV-2 variants of concern (VOCs) harboring multiple mutations in the spike protein raise concerns on effectiveness of current vaccines that rely on the ancestral spike protein. Here, we design a quadrivalent mosaic nanoparticle vaccine displaying spike proteins from the SARS-CoV-2 prototype and 3 different VOCs. The mosaic nanoparticle elicits equivalent or superior neutralizing antibodies against variant strains in mice and non-human primates with only small reduction in neutralization titers against the ancestral strain.

Design of a mutation-integrated trimeric RBD with broad protection against SARS-CoV-2.

The continuous emergence of SARS-CoV-2 variants highlights the need of developing vaccines with broad protection. Here, according to the immune-escape capability and evolutionary convergence, the representative SARS-CoV-2 strains carrying the hotspot mutations were selected. Then, guided by structural and computational analyses, we present a mutation-integrated trimeric form of spike receptor-binding domain (mutI-tri-RBD) as a broadly protective vaccine candidate, which combined heterologous RBDs from different representative strains into a hybrid immunogen and integrated immune-escape hotspots into a single antigen.

Kinetic Characteristics of Neutralizing Antibody Responses Vary among Patients with COVID-19.

Objective: The coronavirus disease 2019 (COVID-19) pandemic continues to present a major challenge to public health. Vaccine development requires an understanding of the kinetics of neutralizing antibody (NAb) responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Methods: In total, 605 serum samples from 125 COVID-19 patients (from January 1 to March 14, 2020) varying in age, sex, severity of symptoms, and presence of underlying diseases were collected, and antibody titers were measured using a micro-neutralization assay with wild-type SARS-CoV-2.

Rapid Development of SARS-CoV-2 Spike Protein Receptor-Binding Domain Self-Assembled Nanoparticle Vaccine Candidates.

The coronavirus disease pandemic of 2019 (COVID-19) caused by the novel SARS-CoV-2 coronavirus resulted in economic losses and threatened human health worldwide. The pandemic highlights an urgent need for a stable, easily produced, and effective vaccine. SARS-CoV-2 uses the spike protein receptor-binding domain (RBD) to bind its cognate receptor, angiotensin-converting enzyme 2 (ACE2), and initiate membrane fusion.

[Cloning and analysis of full-length genes of a H9N2 subtype avian influenza virus isolated from Guangdong].

Eight full-length genes of an avian influenza virus Chinese isolate of H9N2 subtype, A/Chicken/Guangdong/HL/2006 (H9N2) (abbreviated as Ck/GD/HL/06), were amplified by RT-PCR, including the 5' and 3' non-coding region. All the genes were cloned and sequenced. The phylogenetic analysis results showed the HA gene of Ck/GD/HL/06 was located in the same phylogenetic clade as Dk/HK/Y280/97 (H9N2), while the Dk/HK/Y280/97-like viruses had been predominately isolated from chickens in mainland China.