Infectious diseases and disorders of the immune system are a continuous threat to the life and well-being of humans and animals. Studying the fundamental processes in immunology, such as the recognition of self and non-self (e.g. microbes), development of mature lymphocyte receptor repertoires, and the innate and adaptive immune response is crucial for the understanding how the immune system deals with the daily threat of micro-organisms. On the other hand, general knowledge of the highly diverse microbial world is needed. From this knowledge, detailed specific understanding of microbial strategies to circumvent host resistance can be acquired. As a principle, the course will focus on interactions between host and infectious agents. Basic principles as microbial virulence, inflammatory responses, tissue damage and apoptosis are discussed. In addition to normal immune responses to infectious agents, the course will also deal with immunopathological processes and diseases.