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Microbial recognition and the immune response
Other Talks in the Series: The Immune System - key concepts and questions
Primary immunodeficiency disorders
- Dr. Smita Y. Patel
- Oxford University Hospitals, NHS Foundation Trust, UK
Hello, my name is Danna Philpott and I'm an assistant professor in the Department of Immunology at the University of Toronto. In this lecture, I'll present an overview of host microbial recognition systems and how they impact on host immune responses.
This slide provides an outline of the talk. First, I will give a general introduction into innate immunity, looking at the function of Toll-like receptors and Nod-like receptors. We will examine specifically the role of Nod-like receptors in microbial detection. In the second part of this lecture, we will examine the link between innate and adaptive immunity, focusing on how innate signals drive the adaptive immune response.
Before delving into a detailed discussion of innate immunity, I think it's first useful to compare and contrast innate versus adaptive immunity. The innate immune system has been conserved throughout evolution and is present in all multicellular organisms. The adaptive immune system, on the other hand, is fairly recent, and it's uniquely present in invertebrates. In innate immune system, organisms possess a set number of germline encoded recognition receptors. And this is in contrast to the adaptive system where somatic rearrangement of genes allows for the generation of a vast number of recognition receptors or antibodies that can recognize the infinite number of antigens that are present in the environment. Cells of the innate system are immediately able to recognize and react against microbes, whereas the adaptive immune system requires priming. Finally, the innate system has no memory which is unlike the adaptive system which provides a memory of infection.
Eli Metchnikoff in the early 1900s first described phagocytes, one of the key cells involved in innate immunity. He watched as these cells that he had isolated from starfish seek out foreign substances and engulf them. He and many more scientists after him questioned how these cells can recognize that particles are foreign.