COVID-19: guidance for people whose immune system means they

The immune system is the body's tool for preventing or limiting infection Its complex network of cells, organs, proteins, and tissues

The immune system protects organisms from infection with layered defenses of increasing specificity Physical barriers prevent pathogens, such

excretory system The Role of Cytokines in Disease Related to Immune Response Zlatko Immune System—Definition and Development of Immunity 19 ORGANIZATION OF THE IMMUNE SYSTEM

muscular system The immune system responds to antigens by producing cells that directly attack the pathogen, or by producing special proteins called antibodies Antibodies