Ilc or immunology is the branch of medicine that deals with the immune system and its disorders. It covers a wide range of topics from how the immune system works, to how it can be used to fight disease, to its role in transplantation and cancer.
The immune system is a complex network of cells and molecules that work together to protect the body from infection. The main types of cells involved are white blood cells, which can be divided into two main groups: lymphocytes and phagocytes. Lymphocytes include B cells and T cells, which are responsible for producing antibodies and attacking infected cells, respectively. Phagocytes include macrophages and neutrophils, which engulf and destroy bacteria and other foreign invaders.
The immune system also consists of several different organs, such as the thymus, bone marrow, spleen, lymph nodes, and Peyer’s patches. These organs produce white blood cells or help them mature into functioning immunity cell types. In addition, the digestive system (including the gut microbiota) plays an important role in immunity by providing a barrier against pathogens and producing vitamins and other nutrients essential for immune function.
The first line of defense against infection is physical barriers such as skin or mucous membranes (e.g., in the respiratory tract), which prevent microbes from entering the body. If these barriers are breached, innate immunity comes into play – this includes nonspecific responses that kill or limit the spread of invading microbes (e.g., inflammation). If innate immunity fails to clear an infection, adaptive immunity takes over – this involves specific responses that target particular microbes (e.g., via antibodies produced by B cells or killer T cells). Vaccination is a form of adaptive immunity that helps protect against future infections by “teaching” the body to recognize specific pathogens so that it can mount a more rapid response if they are encountered again.