Dr. Jennifer Gommerman is a Professor of Immunology at the University of Toronto. Her team has uncovered a novel gut-brain axis that regulates neuroinflammation and is examining the role of B lymphocytes in Multiple Sclerosis (MS) patients and in animal models of MS. More recently, she has been studying the antibody response to SARS-CoV-2 in saliva samples from patients with COVID-19. She talks about the role of gut-derived plasma cells in multiple sclerosis, and how salivary immunoglobulin A can protect against breakthrough COVID-19 infections.