Introduction to the Immune System

This lecture covers the three lines of immune defense: the epithelial barriers as the first line, innate immunity as the second line, and adaptive immunity as the third line. It explains the role of innate immune cells, such as neutrophils, macrophages, and dendritic cells, in phagocytosis. The lecture also discusses the mechanisms of innate immunity, including phagocytosis, degranulation, interferons, and peptides, as well as the activation of the innate immune system by infectious agents.