Components of Immunity

The first area that we will address regarding immunity is how to identify the components of the immune system which will allow us to know those components that function in the innate and adaptive immune systems. How is the immune system organized? How does the immune system work? In our discussions we will provide answers to these questions. The immune system comprises a coordinated, closed as well as open network of cells, molecules, fluid and compartmentalized organs or domains within the body. Each organ or domain and each cell and molecule has a distinct function for defense. Blood and lymphatic vessels combine to transport cells and molecules into and out of organs to facilitate antigen recognition by B and T cells, cell activation and access of effector molecules and cells with pathogens and their products. Cell adhesion molecules (CAMs) enable cells to interact and communicate, thereby facilitating coordinated responses and movement of cells out of blood vessels and across compartments into tissues, through diapedesis. The various organs, cells, molecules and interconnected network of lymphatic and blood vessels responsible for immunity constitute the immune system. The immune response generated is strengthened by interactions of immune cells with products of the gut microbiome such as the short chain fatty acids (SCFAs), butyrate, propionate and acetate. The cumulative and coordinated response to antigens (foreign and self antigen) resulting in effector function and memory cell development is the immune response. The major components of the immune system include leukocytes for defense. Leukocytes comprise granulocytes which include neutrophils, eosinophils, basophils, mast cells and agranulocytes such as monocytes (including tissue macrophages), lymphocytes and dendritic cells. For example, B lymphocytes secrete antibodies and cytokines, T lymphocytes secrete cytokines and some T cells mediate cytotoxicity. Plasma and lymph is used for transportation of cells and molecules throughout the body. Erythrocytes facilitate the survival of leukocytes by ensuring availability of oxygen for cell respiration and metabolism through gas exchange.