CCAS Researcher Awarded CAREER Grant for Amphibian Study

Leon Grayfer is researching how amphibians fight harmful pathogens at different stages of development.

Leon Grayfer
Leon Grayfer, an assistant professor in the Department of Biological Sciences, recently received an NSF CAREER grant. (Logan Werlinger/ GW Today)
September 04, 2018

By Kristen Mitchell

Leon Grayfer, an assistant professor in the Columbian College of Arts and Sciences, recently received a CAREER grant from the National Science Foundation for his work on amphibian immune responses to a virus that is killing amphibians around the world.

The CAREER award supports promising early career scientists. Dr. Grayfer will receive more than $770,000 from NSF over the next five years to continue his work and incorporate a new lab component into his virology class for undergraduate and graduate students.

Dr. Grayfer and his research group are studying the ramifications of the differences between the tadpole and the adult frog immune cell development on the ability of these animals to overcome infections by a viral contributor to the amphibian decline, the Frog Virus 3 (FV3) ranavirus. Researchers are focusing on the cells of the innate immune system, which is the first line of defense in fighting infectious agents. They have documented several differences between the tadpole and adult frog immune responses to the FV3 pathogen, possibly accounting for the differences in the susceptibility of these two developmental stages. Using a number of molecular approaches, Dr. Grayfer’s lab is currently exploring ways to skew the tadpole and adult frog immune responses toward immunological resistance against this deadly viral pathogen.

Frog Virus 3

Dr. Grayfer’s lab studies the differences between the tadpole and the adult frog immune cell development. (Photo courtesy of Leon Grayfer)


Infectious agents like Frog Virus 3 have detrimental effects on declining amphibian populations around the world. By studying the mechanisms controlling the amphibian immune responses, Dr. Grayfer and his team hope to gain greater insight into what makes these animals more susceptible or more resistant to such pathogen, in order to in turn create potential avenues for developing preventative and therapeutic measures.

“You have the same animal but you have two stages of it, so you can compare and contrast the mechanisms that allow the adult frogs to clear the infection,” he said. “If we understand the differences between how tadpoles and adults generate immune cell types and then functionally, how those cell types contribute to susceptibility and resistance in tadpoles and adults, than we will get a much better idea of what aspects of the tadpole immune response render them less equipped to deal with these pathogens.”

Understanding how this virus affects amphibians at all stages of development is an important step in preserving healthy ecosystems.

“Image a spider web and you pull on one of the threads, amphibians being that thread,” he said. “That spider web is going to change, us being another thread on that web.”

Dr. Grayfer’s research team, which includes a postdoctoral fellow, graduate students, undergraduate students, and high school students, work out of a Science and Engineering Hall lab, where they culture and maintain many different tadpole and adult frog immune cell populations, some of which are susceptible to the virus and others resistant.

In addition to funding his research, the NSF grant he received has a strong educational component. This will allow him to add a lab component to a class he teaches on viruses. As part of this new component, students will engage in experiments and learn lab techniques that will prepare them for future independent research.

Dr. Grayfer said he is honored to receive the CAREER award and is excited to continue this line of research. He is grateful to the Department of Biological Sciences and the university for their continued support.

John Lill, chair of Biological Sciences, said the department is “extremely proud” of Dr. Grayfer. These awards are among the most competitive grants provided by NSF and recognize only the most promising young researchers who often go on to become leaders in their respective disciplines, he said.

“CAREER awards also require a significant integration of research and teaching and we are excited that Dr. Grayfer will be developing a new undergraduate laboratory component to his Virology course as part of this award,” Dr. Lill said. “This award also highlights the significant investment that the department, CCAS, and the university have jointly made in recruiting top-notch researchers to GW.”

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