Kopriva Graduate Student Fellowship Recipients
Ph.D. candidate in statistics, Department of Mathematical Sciences
Kara studies opinion diffusion—the process through which opinions and information spread through online or in-person social networks—on networks of Black men who have sex with men (BMSM) using applied machine learning. BMSM accounted for 25% of HIV diagnoses in the US in 2019, and, while pre-exposure prophylaxis (PrEP) is a critical tool for preventing HIV transmission, PrEP use is low for BMSM. She is working with researchers at the Center for AIDS Intervention Research (CAIR) at the Medical College of Wisconsin, who are leveraging opinion diffusion to combat disinformation and negative PrEP stereotypes in order to increase PrEP use among BMSM. Since existing methods for modeling opinion diffusion were developed for online social networks where data are abundant, Kara developed a novel genetic algorithm to model opinion diffusion using the limited data available in this and other public health applications. Johnson’s current work involves assessing the algorithm’s performance with the issues present in real-world data and developing resources to support use of the algorithm by other researchers.
Alexis’s current research focuses on understanding how conserved patterns found in virus exteriors are used by the host immune system to identify a virus prior to infection. She is working on better understanding how the recognition of these viral exterior patterns alter our immune system’s response to a secondary infection. For example, we know that about a week after an influenza A infection, you are more susceptible to a secondary bacterial infection, which is one of the primary complications associated with influenza A hospitalization and mortality. Interestingly, Alexis has found that this increased susceptibility to a secondary bacterial infection isn’t consistent throughout a flu infection. In fact, she found evidence to suggest that we are even more protected from a secondary bacterial infection than an individual that doesn’t have the flu early on during infection. This is important as bacterial infections complicate many other respiratory viral infections as well. What is particularly important here is that this pattern of susceptibility, particularly early protection, isn’t exclusive to flu and appears to be a generalized response to virus exteriors devoid of genetic material meaning this early protection isn’t dependent on viral infection. Therefore, Alexis is particularly interested in understanding the immune signaling pathway that activates this early protection and improved resolution of bacterial infections. Her primary focus is on studying a pattern recognition receptor called Toll-like Receptor 2/6 (TLR2/6) which she has shown to be involved in the recognition of these viral exteriors. Once this receptor, TLR2/6, recognizes a viral exterior we believe it activates a signaling cascade resulting in the transcription of a variety of genes such as anti-viral genes which in-turn prime the immune system for a secondary bacterial or viral challenge. Collectively, Alexis’s goal for this research is to provide valuable insight into mechanisms of common virus pattern recognition and potentially unique signaling responses that mediate a protective anti-viral and anti-bacterial state. Thus, determining how viruses can elicit anti-viral responses in immune cells prior to infection is critical for development of novel treatments spanning multiple viruses. In addition, if we can determine the mechanism by which early protection occurs then we may be able to determine ways to extend that protection throughout a viral infection thereby protecting individuals from the risk of a secondary bacterial infection.
Colin studies viruses that infect single-celled organisms known as archaea. While researchers have recently gained some understanding as to how these viruses attach to their host cells, how they then enter the cells remains a mystery. Colin has focused on two such viruses — Sulfolobus turreted icosahedral virus (STIV), an enveloped virus with an internal lipid membrane, and Sulfolobus spindle shaped virus (SSV), with a lemon-shaped form. He will use MSU’s new ultra-high resolution cryogenic transmission electron microscope to directly image virus particles in three dimensions as they attach to and deliver genetic cargo into a host cell. For STIV, Colin will investigate the mechanics of how the virus may fuse its membrane with that of its host to release the genome into the cell, like many enveloped eukaryotic viruses. Spindle shaped viruses are hypothesized to inject their genome across the host cell membrane, and Colin hopes to determine how one shaped like a lemon can accomplish this feat. Genome injection studies could provide new approaches to programed payload delivery and have medical and biotech applications.