“My team is starting on this immediately,” says Dr. Poland. “We will be collaborating with the Butantan Institute in Brazil and its director Jorge Kalil, M.D., Ph.D. They are the largest immunobiology lab in Latin America and produce 90 percent of the vaccines in Brazil. “
“We are very pleased to be working with Mayo Clinic on this urgent project,” says Dr. Kalil. “We hope to find an answer to this growing problem.”
According to the Centers for Disease Control and Prevention the virus, carried and spread by mosquitos, is believed to have been the cause of an increased level of birth defects, specifically microcephaly – infants with smaller than normal heads – and Guillain-Barré syndrome. It was first reported in Brazil in 2015 and has spread to many countries in Latin America. It was previously active in Asia, Africa and the Pacific Islands.
The Mayo Clinic Vaccine Research Group has been active in advancing discoveries in influenza, rubella, measles and smallpox. There is currently no vaccine for the Zika virus and no treatment for stemming potential birth defects once a woman has been infected.
“My lab designed a way to identify the pieces of a virus that our immune cells respond to and develop immunity against,” says Dr. Poland. “We’ve done that with measles and smallpox. We’ll use that same platform to develop a zika vaccine.”
The Mayo team will use a mass spectrometry approach to study human cells infected with the virus. As the cells process and break down the virus into component pieces, says Dr. Poland, the researchers use mass spec to pull out and identify an array of peptides. The Vaccine Research Group developed a methodology to identify the components that a T-cell sees. That’s the immune system’s primary defensive cell. The team then uses that information about the peptides to reverse engineer a vaccine.
Dr. Poland says developing a peptide-based vaccine has its pros and cons.
“Humans don’t respond well to peptide vaccines so we will package the vaccine with an adjuvant to enhance the process. We are currently working with the Karolinska Institiutet to develop packaging using nanoparticles. That may be an option. If not, we will probably use a chemical adjuvant.”
“If we are right, it will be a very easy and inexpensive vaccine to make. There’ll be no contraindications or risks as with a live virus vaccine and this will be easy to transport, won’t need refrigeration and will have a long shelf life. You can store peptides almost forever and reconstitute them when the vaccine is needed.”
Dr. Poland says that will be handy as the Zika virus flares up in a population and then moves on, so when and how any vaccine would be deployed is still being discussed.
March 8, 2016