Jacobs School Immunologists Win Big at Society Meeting

The society, which promotes research and study of leukocyte biology and immunology, held its annual meeting in late October at Michigan State University in East Lansing, Michigan. 

Essi Y. I. Tchalla, a microbiology and immunology doctoral student in the lab of Elsa Bou Ghanem, PhD, received the Presidential Scholar award, a merit-based award recognizing graduate, undergraduate, and postdoctoral researchers and their work.

Tchalla came to UB as an undergraduate from Togo in West Africa. Her interest in microbiology and immunology stemmed from a course on the subject taken her senior year. She is now at the end of her doctoral journey and wants to pursue a career in vaccine and antibody development, hoping to help advance the delivery of safe therapeutic interventions.  

At the meeting, Tchalla presented research titled “Neutrophils Control T Cell Responses to the Pneumococcal Conjugate Vaccine.” This work addresses challenges posed by pneumonia and pneumococcal infections, which cause high disease burden worldwide despite existing vaccines.

Tchalla is looking at how neutrophils, the most abundant white blood cells, help induce appropriate immune responses to vaccines.

Using the pneumococcal vaccine Prevnar, she investigated the role of neutrophils in T cell responses to the vaccine. She found that neutrophils influence the amount of regulatory T cells (Tregs) present, which typically limit and control immune responses.

By balancing Treg response, neutrophils help ensure production of adequate and protective antibodies following Prevnar immunization. Therefore, because of their influence on Tregs and the adaptive immune response, neutrophils could be novel targets for more effective vaccines, Tchalla says.

“As a graduate student, it is always rewarding to receive accolades and recognition, not only from your fellow trainees but your scientific community at large,” Tchalla says. “Knowing that I was voted for by my peers and scientific elders was truly amazing and a great reminder that my work matters.”

Shaunna Simmons, also a microbiology and immunology doctoral student in the Bou Ghanem lab, is studying how age affects the immune system and can increase disease susceptibility.

While attending the conference, she presented research that also explores the role of neutrophils and vaccine response. Her research on “Changes in Neutrophil Signaling Pathways Controlling Pneumococcal Killing in Vaccinated Aged Hosts” received the Trainer Flash Talk award in the host-pathogen dynamics category. 

While the effectiveness of available pneumococcal vaccines declines with age, Simmons is exploring how neutrophils could influence efficacy. She and her colleagues examined how certain neutrophil signaling pathways change with age.

By focusing on how the MAPK pathway differed between young and old mice, she observed that older mice had irregular MAPK pathway activity. The older mice had increased levels of ERK1/2, a key pathway component, coupled with reduced activation and response to target bacteria.

After inhibiting ERK1/2 in older mice, their neutrophils had increased ability to kill Streptococcus pneumoniae, the bacteria behind pneumococcal infection, Simmons found.  

“This was my second time attending the Society for Leukocyte Biology meeting, and, as a member, I have also been able to attend several virtual events and seminars through this organization,” Simmons says. “After winning the award, it felt nice to be recognized for my research by the other members of the SLB community.”  

At the society meeting, Elizabeth A. Wohlfert, PhD, associate professor of microbiology and immunology, shared research on how long-term infection can affect muscle regeneration. She received the Excellence in Leukocyte Biology award.

Wohlfert, who’s long studied regulatory T cells, has been exploring how Tregs change during Toxoplasma gondii infection of muscle tissue in mice. During infection, as opposed to acting as immune suppressors and dampening inflammation, some Tregs essentially become bad actors, actively participating in the inflammatory response. 

To dig deeper, she and her colleagues compared Tregs from three types of muscle tissue: injured tissue, chronically infected tissue, and chronically infected tissue that was also injured.

After conducting a transcriptomic analysis, which analyzes RNA, Wohlfert observed different subsets of Tregs and, notably, found that one subset was always absent in the presence of infection. This observation, along with further understanding of Tregs and these subsets, could shed light on muscle regeneration and repair, especially as it relates to infection.

“A lot of our understanding about muscle regeneration is largely in the context of sterile, or non-infectious, injury,” says Wohlfert, who also directs the department’s graduate studies program. “But it’s important to understand how infection impacts muscle homeostasis and ability to respond to injury.”