Researchers have created a vaccine that can induce a strong antibody response against SARS-CoV-2. The vaccine, which has been tested in mice, consists of a DNA scaffold that carries many copies of a viral antigen.

This type of vaccine, known as a particulate vaccine, mimics the structure of a virus. Most previous work on particulate vaccines has relied on protein scaffolds, but the proteins used in those vaccines tend to generate an unnecessary immune response that can distract the immune system from the target.

In the mouse study, the researchers found that the DNA scaffold does not induce an immune response, allowing the immune system to focus its antibody response on the target antigen.

This approach, which strongly stimulates B cells (the cells that produce antibodies), could make it easier to develop vaccines against viruses that have been difficult to target, including HIV and influenza, as well as SARS-CoV-2, the researchers say. Unlike T cells, which are stimulated by other types of vaccines, these B cells can persist for decades, offering long-term protection.

The researchers are developing scaffolds made using DNA origami, a method that offers precise control over the structure of synthetic DNA and allows researchers to attach a variety of molecules, such as viral antigens, at specific locations.

In the new study, the researchers swapped in an antigen consisting of the receptor binding protein of the spike protein from the original strain of SARS-CoV-2. When they gave the vaccine to mice, they found that the mice generated high levels of antibodies to the spike protein but did not generate any to the DNA scaffold.

In contrast, a vaccine based on a scaffold protein called ferritin, coated with SARS-CoV-2 antigens, generated many antibodies against ferritin as well as SARS-CoV-2.

To that end, the researchers are now exploring whether a DNA scaffold with many different viral antigens attached could induce broadly neutralizing antibodies against SARS-CoV-2 and related viruses.