Immunology defines an area of biology that deals with the immune system of organisms and finds application in a variety of disciplines. It plays an important role in medicine, especially in oncology, virology, rheumatology and many more. The main focus of immunology is the research of the physiological function of the immune system and the analysis of the immunological state in health and disease.
Immunological research includes the complex cellular and humoral immunity as well as their cooperation of the physiological and biochemical processes in the whole organism associated with an immune response. The immune reactions can be triggered by contact with infectious pathogens or other antigens. Immune cells, derived in the mone marrow from hematopoetic stem cells are the key player in controlling the immune response to pathogenic antigens. Pluripotent hematopoietic stem cells can generate lymphocytes, which are responsible for adaptive immunity, and myeloid lineages, which are involved in both innate and adaptive immunity. The myeloid lineage gives rise to neutrophils, basophils and eosinophils, also called granulocytes, macrophages and dendritic immature cells act as effector cells for infection and inflammation. The main function of macrophages is the phagocytosis of bacteria and the recruitment of other phagocytic cells whereas mast cells are involved in the defense against parasites and the recruitment of eosinophils and basophils. Another important group of myeloid lineage derived cells are the dendritic cells. After they enter the tissue as immature phagocytes, they become specific for antigen uptake and migrate into the lymphatic tissue as antigen-presenting cells. Upon antigen presentation, T-lymphocytes and B-lymphocytes immediately start proliferating and differentiate into antigen-specific effector cells (T-cells) and antibody secreting cells (B-cells), repsectively.