Nanoengineers at the University of California San Diego have
developedCOVID-19vaccine candidates that can take the heat. These
fridge-free vaccines are made from a plant virus called cowpea mosaic
virus and the other is from a bacterial virus or bacteriophage.
The two vaccines were made using similar recipes. The researchers used
cowpea plants and/Escherichia coli/bacteria to grow millions of copies
of the plant virus and bacteriophage, respectively, in the form of
ball-shaped nanoparticles. They harvested these nanoparticles and then
attached a small piece of theSARS-CoV-2 spike protein to the surface.
The finished products look like an infectious virus so the immune system
can recognize them, though they are not infectious in animals and
humans. The small piece of the spike protein attached to the surface
stimulates the body to generate an immune response against the coronavirus.
The researchers note several advantages of using plant viruses and
bacteriophages in making vaccines. The process can be easy and
inexpensive to produce at large scales. Another big advantage is that
the plant virus and bacteriophage nanoparticles are extremely stable at
high temperatures and the vaccines can be stored and shipped without
needing to be kept cold.
These new COVID-19 vaccines are still in the early stages of
development, but the researchers found that in mice, the vaccine
candidates triggered high production of neutralizing antibodies against
These Fridge-Free COVID-19 Vaccines Are Grown in Plants and Bacteria