Electronic Thesis and Dissertation Repository

Thesis Format

Monograph

Degree

Master of Science

Program

Microbiology and Immunology

Supervisor

Dekaban, Gregory A.

2nd Supervisor

Brown, Arthur

Co-Supervisor

Abstract

Neurotrauma is a debilitating injury, and no treatment currently exists that improves both physical and neurological recovery. A novel immunomodulatory therapeutic agent – anti-CD11d – has been developed at Robarts Research Institute. Application of anti-CD11d therapy following injury decreases the infiltration of peripheral leukocytes into the injured central nervous system, improves physical recovery, and improves neurological recovery in rodent neurotrauma models. The binding and signalling mechanisms of anti-CD11d on leukocytes, however, remain poorly understood. An endogenous CD11d/CD18 expression model was established in differentiated THP-1 cells to investigate anti-CD11d mechanisms. Immunocytochemistry and Förster Resonance Energy Transfer (FRET) microscopy characterized anti-CD11d binding to active and inactive CD11d/CD18 conformations. Western blot analysis did not detect CD11d/CD18 signalling through tyrosine kinases following stimulation with low or moderate concentrations of soluble anti-CD11d (CB1/CA1). Overall, my study will inform the development of anti-CD11d acute neurotrauma therapy and provide new tools to investigate basic CD11d/CD18 biology.

Summary for Lay Audience

Neurotrauma is an injury to the brain or spinal cord, which can have debilitating and lasting impacts on a patient. Unfortunately, no treatment exists that can improve both the physical injury and the neurological defects in motor function, pain sensitivity, and blood pressure regulation. A key problem with neurotrauma injuries is the attack of the body’s own activated immune cells on the injury site, which exacerbates the injury. An exciting new treatment called anti-CD11d has been developed at Robarts Research Institute that uses an antibody to reduce the migration of immune cells to the site of injury. The antibody targets a protein called CD11d/CD18, which helps regulate the migration of immune cells throughout the body. Application of anti-CD11d blocks the ability of CD11d/CD18 to bind other proteins and pull immune cells from the blood into the injured brain or spinal cord. Anti-CD11d acute neurotrauma therapy can be applied following neurotrauma and it improves both the physical and neurological recovery in rodent models. Our understanding of the molecular interactions between anti-CD11d and its target CD11d/CD18, however, are not well understood. The goal of my study is to characterize these molecular interactions between anti-CD11d and CD11d/CD18 to progress the development of the treatment. First, CD11d/CD18 can be found on the surface of immune cells in an active or inactive form. I used advanced microscope techniques to detect anti-CD11d binding to both active and inactive CD11d/CD18. Second, CD11d/CD18 can induce signals within immune cells that cause the induction of damaging inflammation. I used a human immune cell model and found that neither low nor moderate concentrations of anti-CD11d induced CD11d/CD18 signals. Overall, understanding these molecular interactions between anti-CD11d and CD11d/CD18 is important in characterizing both intended and off-targeted effects of anti-CD11d during its exciting and on-going development.

Available for download on Thursday, May 16, 2024

Share

COinS