By Danealle Parchment, postbac in the Virology Core Section of the Virology Laboratory, Vaccine Research Center
On November 4, 2021, Leah Katzelnick, Ph.D., M.P.H., presented (virtually) at the NIAID Postbac Research Seminar Series—an opportunity for NIAID postbacs to engage with principal investigators (PIs). Dr. Katzelnick is an Earl Stadtman Investigator, NIH Distinguished Scholar, and chief of the new Viral Epidemiology and Immunity Unit in the Laboratory of Infectious Diseases. Danealle Parchment, an NIAID postbac in the Virology Lab of the Vaccine Research Center, reflects on the seminar and captures the advice for early-stage scientists shared by Dr. Katzelnick.
Dr. Katzelnick’s fascination with dengue originated when she contracted the virus while in Nicaragua writing her undergraduate anthropology thesis in 2009. She eventually developed dengue hemorrhagic fever, a severe form of dengue disease. Dengue virus (DENV) is a flavivirus, a genus of positive-strand RNA viruses, that has four known serotypes: DENV1-4. Each serotype is a distinct lineage and within each serotype is a great deal of genetic variation. Infection with one dengue virus serotype generally protects you from reinfection with the same serotype. However, it appears that dengue uses its collection of serotypes to its advantage. If you are infected with a different dengue serotype, antibodies from the first infection can increase the severity of your second dengue infection—this phenomenon is known as antibody dependent enhancement (ADE) and makes dengue vaccine development an arduous task.
Dr. Katzelnick’s lab studies dengue viruses using a three-pronged approach. She focused on the first approach in this seminar, viral antigenic evolution, which examines how viral antigens evolve according to immunity over time. They evaluate this question using antigenic cartography, the process of calculating antigenic distances between dengue virus serotypes and positioning them on a map. Researchers use neutralizing antibody titers as a proxy for distance between viral antigens, which highlights antigenic differences between viruses. Through her work with global collaborators, Dr. Katzelnick and her team discovered that dengue viruses cluster antigenically but not as discrete serotypes. Thus, immune system recognition of DENV is more diffuse than originally believed based on genetic data alone, which focused on nucleotide sequences and envelope amino acid difference published in Katzelnick, Leah C et al. Science 2015.
Current studies in Dr. Katzelnick’s lab focus on identifying individuals who can safely receive existing dengue vaccines and developing new ones that are safe and effective for dengue-naïve individuals. Many of these projects are spearheaded by postbac fellows, allowing them to develop research independence, experience essential to growing into strong scientists.
After she finished her research talk, Dr. Katzelnick provided great advice for young scientists who have thought about switching research interests. Moving from anthropology to virology involved a steep learning curve, but her previous field experience proved beneficial when working with people from around the globe: “If you’re really passionate about something and it’s an emerging field, there’s an opportunity to become an expert.” Dr. Katzelnick’s talk showcased the best parts of conducting research and encouraged those starting out that you can do anything if you have the passion.