(4ae) Engineered Immunocytokines Improve Delivery of IL-2 to Pro-Inflammatory Cells and Promote Anti-Tumor Activity.

Interleukin 2 (IL-2) is a powerful cytokine that plays a pivotal role in the development, maintenance, activation and proliferation of T cells. Upon encountering their cognate antigen, effector T cells require IL-2 stimulation for effective activation and proliferation. T regulatory cells (T_regs)—which are responsible for suppressing inflammatory responses and maintaining tolerance to self—are even more sensitive to IL-2 levels than effector T cells. In tumors, this increased sensitivity to IL-2 allows T_regs to deplete the IL-2 levels within the tumor, which can prevent potentially tumor-reactive effector T cells from mounting an inflammatory immune response to clear the malignant cells.

Because IL-2 plays such an essential role in stimulating both pro- and anti-inflammatory responses, this cytokine has great potential for immune disease treatment. However, on its own it has an incredibly rapid clearance, and its indiscriminate activity on both effector and regulatory T cells limits its therapeutic performance.

To address these shortcomings, we have engineered an IL-2 specific antibody that biases cytokine activity toward immunostimulatory functions. By modulating the interactions between IL-2 and its receptor, the antibody can eliminate the sensitivity advantage of T_regs. Moreover, complexing IL-2 with an antibody simultaneously prolongs cytokine half-life. Previous work using an anti-mouse IL-2 antibody demonstrated that IL-2/antibody complexes stimulated potent preferential expansion of effector T cells compared to T_regs, leading to inhibition of tumor growth in vivo.

We first engineered an IL-2-specific antibody—602—to more effectively bias the interaction with the IL-2 receptor using a yeast surface display. We tethered the improved variant, F10, and the parental 602 to IL-2 with an optimized Gly₄Ser linker that fused the C-terminus of IL-2 to the N-terminus of the antibody light chain. This tethered IL-2-antibody molecule, or immunocytokine (IC), will reduce potential off-target effects by preventing IL-2 from dissociating away from the antibody, and as a single molecule therapeutic, is streamlined for translation. We have shown that both the parental 602 IC and the engineered F10 IC vastly improve that bias towards immunostimulatory CD4+FoxP3- effector T cells (Fig. a, c-d) and CD8+ T cells (Fig. b-c, e) in primary human mononuclear cells, as compared to IL-2 and a control IC in which an irrelevant antibody was fused to IL-2, and there is no intramolecular binding. The engineered F10 IC shows additional improvement in bias compared to parental 602, and had the lowest potency of any of species tested on T_Regs. F10 IC also potently drives preferential expansion of CD8+ T cells over T_Regsin vivo (Fig. f), resulting in increased therapeutic efficacy in the suppression of tumor growth in the B16F10 mouse tumor model (Fig. g).

Teaching Interests

Due to my passion for hands-on experimentation, much of my teaching and mentoring experience has been project-, laboratory-, or research-based. As an undergrad, I was a proctor in the machine shops, and supervised and assisted other students with machining for and building their design projects. As a graduate student, I served as a teaching assistant for a variety of broad biomedical lab courses that covered basics of biomaterials and drug delivery, programming, biomechanics, tissue culture and basic mammalian cell assays, and biomedical imaging. I synthesized lecture and design-oriented group projects as a TA for Engineering Global Health. Though I enjoyed assisting in designing course content in both situations, my role in the global health course was much larger, and I assisted in planning course content and devising the design project prompts, and also had a significant role in classroom instruction. The older students in this class expressed that this was the first time they felt like they were really doing the engineering that they had imagined when they chose to pursue an engineering degree, and they were the most enthusiastic students in the class. The younger students, who largely were very quiet in the first weeks of the class, experienced tremendous growth over the semester, and by the end were active participants in discussions, and presented their projects confidently. Some of the younger students enjoyed this course so much that they began to participate in research. I mentored two of those students in the subsequent years, and taught them the basics of the immunoengineering research I was doing, and trained them in a variety of the common techniques we used.

Those experiences prompted me to pursue a teaching-intensive postdoctoral fellowship, which has allowed me to gain substantially more experience in developing course material, delivering lectures and guiding discussions. I have been the assistant instructor for another two courses with significant lab-based components, but have worked from the opposite angle of bringing lab-based practical understanding to the lecture content. Specifically, I incorporated specific information about SARS-CoV-2 into topics like viral replication and transmission and understanding the biochemical and structural basis of receptor-ligand interactions as one of the instructors for Molecular Biology. Beyond weaving lived and lab-based experience into the lecture content, I also developed animations that illustrated techniques and concepts that are often difficult to describe or illustrate through static diagrams. The students responded well to these, and were much more able to rapidly identify elements within the process that they didn’t understand fully, or had more questions about. Overall, I feel both strategies motivate and facilitate the students actively engaging in the content we are trying to convey, and create a more memorable experience of the science, that they will be able to build on as they advance through their academic and professional careers.

Outside of any university classrooms, I engaged in several outreach experiences with local elementary school students or Girl Scout troops. In each, I interactively explained and showed the basic parts of an analog camera as I deconstructed it, and then dissected a cow eye while asking which parts of the camera the kids thought each part of the eye was most functionally similar to. They were then allowed to dissect their own cow eye and camera, and see first-hand the similarities between the two.

The aspect of teaching that has been the most rewarding throughout is the ability to activate creativity, ingenuity and excitement in students. I love to find problems and topics that ignite them, that make them want to brainstorm and work together, and come up with something that they are proud of. I love when I am able to find a project that the students want to work on, because they enjoy working on it, and not because they want a particular grade or to pass the class. As much as I know that mastering theory is essential to biomedical engineering competence, the application of this theory is what energizes most students, and is why many of them were first drawn to the major.

I will be co-instructing the Molecular Biology class again this fall, and look forward to developing more animations, and testing whether these do in fact facilitate more rapid understanding of the concepts they illustrate. I would love to gather more experience in designing project-based courses, and in coming up with projects that can take advantage of the resources and current events that are most likely to engage and excite students. I would also like to develop guided methods to expedite student-driven investigations, so that they can have a more real-world research experience within the time constraints of a semester-long course.