All Episodes
1. Introduction to the Immune System
This episode gives a concise overview of the human immune system, starting with its fundamental purpose: defending the body against pathogens and internal threats. The document first outlines the immune system's ability to distinguish between self and non-self tissues, with the focus shifting to the key roles of innate and adaptive immunity. The document describes how the innate immune system, a first line of defence, operates through physical barriers, soluble proteins, and cellular responses. This contrasts with the adaptive immune system, which develops specific, long-lasting immunity through lymphocyte-mediated responses. The final section delves into lymphocyte organisation, describing how these cells develop, circulate, and interact with antigens to initiate the crucial process of clonal selection—a key mechanism by which the immune system generates specific responses to specific threats.
2. Innate Immunity I
This episode outlines the fundamentals of innate immunity, the body’s first line of defence against pathogens. It begins by establishing innate immunity as an ancient and ubiquitous system, present across various species. The document then explores key elements of this system, starting with physical barriers such as skin and mucous membranes that act as the first line of defence. It then delves into pre-formed mediators, proteins or peptides with broad specificity, that contribute to pathogen damage, inflammation, and immune cell activation. This includes a detailed explanation of the complement system, a crucial component of innate immunity, and its activation pathways, biological activities, and regulatory mechanisms. The document concludes by highlighting the importance of complement in combating infections and its interplay with the adaptive immune system, emphasizing its relevance in various diseases, including autoimmune diseases, allergies, and even severe COVID-19.
3. Innate Immunity II
This episode specifically focuses on the cells and mechanisms that make up this crucial first line of defence against pathogens. It begins by describing the different types of innate immune cells, including polymorphonuclear leukocytes (PMNs) like neutrophils, eosinophils, and basophils, as well as monocytes, macrophages, dendritic cells, and natural killer (NK) cells. These cells each have unique roles in identifying, engulfing, and destroying pathogens, and their functions are further explained in detail, including their specific receptors and the methods they employ to combat infection. The document goes on to explain the process of phagocytosis, the engulfing of pathogens, and the bactericidal agents used by these cells to kill invading organisms. Finally, it delves into the crucial topic of pathogen recognition, highlighting the key role of pathogen recognition receptors (PRRs) in detecting specific molecular patterns associated with microbes (MAMPs) and damage (DAMPs). The document ultimately aims to provide a comprehensive overview of the intricate and dynamic innate immune system, emphasizing the importance of these cells and mechanisms in protecting the body from infection.