Date of Award

January 2023

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Biomedical Sciences

First Advisor

David S. Bradley

Abstract

Immunotherapies now stand at the forefront of cancer treatment as a versatile arsenal of cutting-edge tools wielded by medical professionals to combat and conquer a spectrum of formidable diseases. Most notably, immunotherapies such as immune checkpoint inhibitors, have revolutionized the field of oncology offering a promising alternative to conventional treatments like chemo and radiation therapy with significant improvements for patients in terms of quality of life and survival. Immunotherapies can be uniquely personalized to a patient's genetic and immune system profile leading to more effective treatments and durable long-lasting responses. Our research group has identified Staphylococcal enterotoxin I as a potent T cell activator that drives multifaceted antitumor responses but has not been incorporated into the arsenal due to the risk of HLA-associated toxicity. The following work aims to understand further and reduce that risk. HLA-DQ8 mice with established B16-F10 tumors receiving 25µg of SEI on days 6 and 9 post-tumor implant resulted in an astonishing 100% progression-free survival for greater than 400 days. However, SEI cancer immunotherapy was not successful in HLA-DR3 humanized transgenic or allogenic C57BL/6 mice. Furthermore, HLA-DQ8 mice rechallenged with 2.5x105 live B16-F10 cells experienced 100% survival for greater than 100 days post-implant. However, SEI immunotherapy was only limitedly effective against established Lewis lung carcinoma and did not provide cross-protection against rechallenge with either LLC or TC-1 tumor cell lines. The studies presented herein demonstrate that single superantigen SEI immunotherapy elicits antitumor responses against melanoma and supports further investigation into clinical applications of superantigen-based immunotherapies.

Available for download on Friday, January 23, 2026

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