Vaccines Containing Genes Could Offer Advantages in Preventing Infectious Diseases
Vaccines for infectious diseases contain weak or dead proteins or pathogens from the disease-causing microorganisms. The vaccines that fight cancer rely on proteins as well. However, scientists have created a new type of vaccine that contains genes and is expected to offer several advantages over its standard predecessor. After decades of research, genomic vaccines are being used in clinical trials.
How It Works: Protein vs. Genomic Vaccines
Protein-based vaccines deliver weak or dead pathogens into the bloodstream so that the immune system can learn to recognize the antigen proteins on the surface as foreign microorganisms. In some cases, vaccines contain only the antigens. The purpose is to prepare the immune system to take action the next time that the antigens are present. In the treatment of cancer, vaccines contain antibody proteins that improve how the immune system responds.
The new genomic vaccines achieve the same end in a different way. They contain genetic material with coding sequences for the desired proteins of one or more diseases. When the DNA or RNA is injected, it enters cells and stimulates them to produce the target proteins.
What This Means for Preventing Infectious Diseases
Currently, vaccine proteins are made in cell cultures or eggs. By using genetic material in vaccines, manufacturers can make them faster and cheaper. Also, one vaccine can include the genetic codes for multiple proteins. The codes can be changed to address pathogen mutations or if new properties are necessary to fight a disease.
For example, the public health industry modifies the flu vaccine every year. However, their changes don't always match the viral strains that circulate during flu season. With genomic vaccines, they can sequence the genetic material according to the strains that are circulating. Furthermore, the new vaccines can be altered and manufactured quickly when viruses such as Ebola or Zika become more widespread or deadly.
Genomic vaccines allow for passive immune transfer as well. In this twist on vaccinations, antibodies are injected instead of antigens. This works by identifying people whose bodies resist a specific pathogen and then isolating the antibodies that protect them. Scientists can then design gene sequences that stimulate cells to produce the antibodies.
Genomic Vaccines Move Into Clinical Trials
The American government, small and large companies, and academic labs are heavily investing in this technology. In a study, scientists used a messenger RNA vaccine. They encapsulated the Zika virus mRNA in a lipid nanoparticle, and it prompted protective immune system responses in mice and primates.
Several clinical trials are also underway to test the immunogenicity and safety of genomic vaccines. Some of the diseases that they're testing with include
- avian influenza,
- breast cancer,
- hepatitis C,
- lung cancer,
- pancreatic cancer,
- prostate cancer, and
Working to Improve the Technology and Other Advancements
At the same time, other scientists are trying to improve the technology. They want to find even more efficient ways to insert the genes into cells and make the vaccines more stable in heat. They're also studying nasal administration as an alternative to injection.
Meanwhile, Synthetic Genomics scientists have developed equipment that quickly produces DNA, RNA, viral particles and protein drugs from digitally encoded biological information without human intervention. The prototype digital-to-biological converter requires two or three more years of work before it's commercially available. However, the company hopes that it will allow a desktop instrument to produce complex biological materials on-site. Such technology could further benefit genomic vaccine production in the future.