Cells of the innate immune system

Published on July 29, 2021   43 min

Other Talks in the Series: The Immune System - Key Concepts and Questions

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Hello, my name is Kevin Maloy and I'm a professor of mucosal immunology at the University of Glasgow. My lab has a longstanding interest in mucosal immunology, with a particular focus on the regulation of innate immunity in the intestine. In this lecture, I aim to provide an overview of the cells of the innate immune system, and outline their key roles in various aspects of host immunity and tissue protection.
In this lecture, I plan to cover four key themes. First, I will give an overview of what the innate immune system is, and why it's necessary. Then I'll describe the various different cell types of the immune system in turn, and outline their key functions, as well as their mechanisms of action. I will also discuss how the innate and adaptive immune systems are integrated, throughout the different stages of immune responses.
The innate immune system encompasses a range of distinct mechanisms that protect host tissues from infection or trauma. Some of these mechanisms are constitutive, such as secretion of stomach acid and mucus, to protect the gastrointestinal tract from infection. For any pathogens that pass across body barriers, there are additional innate mechanisms in plasma, like the complement protein cascade that can bind and kill bacteria. In addition, throughout the body, a diverse array of innate leucocytes can be quickly called into action to deal with the threat, and these will be the primary focus of this lecture. Innate immunity is responsible for the rapid responses that are elicited by infection or trauma, and that lead to acute inflammation. Innate immunity is often termed 'non-specific', because unlike the highly specific responses mediated by T and B lymphocytes, innate sensing pathways do not focus on unique antigens expressed by different individual pathogens, but instead utilise conserved germline receptors to sense different classes of pathogens. Innate immunity does not exhibit the classical immunological memory responses of B and T lymphocytes. It's important to stress that the innate and adaptive arms of the immune system work in tandem, with early innate responses helping to instruct subsequent T and B cell responses. In turn, these adaptive responses recruit and activate innate leucocytes, to mediate protective effector responses against infection.