This book synthesizes the key concepts of immunosuppression and immunomodulation. A comprehensive understanding of these processes is necessary to develop vaccines and therapeutic interventions for diseases. This book examines the role of information molecules such as cytokines and chemokines and other proteins secreted by the host upon interacting with the pathogen(s) that modulate and suppress the immune system and assist the pathogen(s) in causing disease. Chapters discuss the modulation of inflammation, signaling pathways, the interaction of immune cells, and resulting immunity as well as its suppression.