Breaking Down Vaccine Development With an Assay Expert

Maria Dennis, a research analyst in the Permar Lab at Duke University Medical School, is developing vaccines that prevent the spread of HIV from mother to child during the perinatal period.

These days Maria and her team work in shifts, only coming into the lab when absolutely necessary. When she does go into the lab, Maria runs experiments, records data in LabArchives and then returns home to analyze it all online. The Permar lab has quickly adapted to this new landscape and, at the same time, the work that they do has become even more relevant. 

Maria Dennis.

While vaccine development has been talked about quite a bit this year, the steps that make up the process can still be hard to understand. “The goal of a vaccine is to prime your immune system to produce antibodies that will fight off a virus if you become infected,” Maria said. She works backwards towards that goal by investigating magnitude, functionality and scheduling.

Magnitude refers to the quantity of antibodies a vaccine elicits. When a vaccine is administered, Maria first measures the amount of antibodies produced by the immune response. If none are produced, the vaccine didn’t work as expected. If some antibodies are produced, it may have worked. From there she looks at those antibodies’ functions.

Functionality is a measure of what the produced antibodies can ‘do’ when it comes to fighting viruses, which have many different strains. Can the antibodies fight only one strain? Five strains? Fifty strains? The more strains a vaccine can repel, the more functional it is. If a vaccine Maria develops is high in both magnitude and functionality she then moves on to test scheduling. While this is happening Dr. Permar and other Primary Investigators (PIs) in the lab look at previous studies to determine the best immunization schedule – there are quite a few moving parts.

Scheduling is the ‘big picture’ stage of vaccine development where scientists ask all kinds of questions about when a vaccine should be given and what kind of effect it could have on other regularly administered vaccinations. When Maria finds a vaccine that elicits a high number of antibodies and can suppress many different HIV strains, she then analyzes how that vaccine interacts with others. In the context of her study this is highly important as infants often receive many vaccines early on. Scheduling is specific to each vaccine and determines when and how often they are given. 

The basic stages of vaccine development are hopefully now more clear. But what does this analysis actually look like in the lab? At the bench it involves assays which, as Maria says, require a lot of pipetting. The 96 well plate, or in her case a 384 well plate, is one of the essential tools that you may have even seen on the news. “It may not be as exciting as Hollywood portrays it,” Maria said, “but the small breakthroughs and troubleshooting are what I enjoy most about this work.”

Maria is a binding assay expert. “Assays are tests essentially, different types of assays are used to get different types of data,” she explained. “Let’s say we have a cat that was immunized with a vaccination that should prevent it from being infected with HIV. A few weeks after vaccination they’re injected with the virus. Blood samples then comes to me and I run a specific assay to see what the resulting antibody levels are.” If there are a lot of antibodies the vaccine strategy may be worth pursuing further. 

From there Maria uses different types of assays to answer functionality and scheduling questions. All things going well, these samples will eventually go to someone who performs neutralization assays to see if the antibodies elicited can neutralize different levels of virus. Eventually, they may be included in a vaccine. 

Maria doing some assay testing with a 384 well plate.

Maria finds this study very challenging and looking back on it, she’s pretty happy she stumbled into it. After finishing her biology and chemistry studies in 2016 she started applying to jobs and ended up interviewing Dr. Permar about her own path. Dr. Permar asked Maria to send her resume into the lab manager and after an interview, Maria found herself with a job at the lab itself. She now has five years of experience under her belt and will soon pursue a Masters of Public Health and her MBA.

Vaccines have become a hot topic as a result of COVID-19 and being able to translate what a vaccine does and how they are developed is important, Maria mentioned. “It does take a while to develop vaccines. There are a lot of people working on the COVID-19 one but we do have to answer a lot of questions in these trials. We need a good biological response and safety as well. Translating those steps is key.” Vaccine development, as Maria put it, isn’t really like a sudden ‘ah ha’ or light bulb moment. “It’s more like the light bulb comes on faintly and then gets brighter and brighter gradually.”