Immunologists are the medical scientists who specialize in the field of immunology. This branch of medicine deals with all the aspects of the immune system: its physiological functioning, its physical and chemical characteristics, and disease immunity. Immune system is the system of organs, tissues and cells within an organism that protect it from infection by foreign substances and pathogens. Immunologists study the medical conditions that involve the immune system like autoimmune diseases, immune deficiency, allergies and transplant rejection. They investigate the functions of the immune system and help to diagnose the diseases and disorders that arise due to the malfunction of this system. They analyze the components of the immune system such as cells, antibodies and proteins, and aid in the development of new drugs, vaccines, therapies and treatments to treat abnormal immune conditions. Immunologists primarily work in laboratories and conduct experiments on cells, genes, antibodies, etc. and test their interactions. In clinical settings they work with the patients by diagnosing and helping them in the management of immunological disorders. They work in collaboration with laboratory staff like biomedical scientists and immunology nurses to undertake a range of experiments and activities to monitor and treat these patients. Immunologists are also employed in medical universities and research institutes. Read on to learn about the life and works of various famous immunologists from all over the world.