Summary Basic Immunology: Functions and Disorders of the Immune System

Immunology is the study of immune system including its responses to microbial pathogens and damaged tissues and its role in disease l Immunity is the ability of the host to protect its self against exogenous or endogenous pathogens Viruses, Bacteria, Fungi, Parasites and Toxins l The immune system comprises tissue, cells and molecules which mount the immune response Introduction l The most important physiologic function of the immune system is to prevent infections and to eradicate established infections l Stimulating immune responses against microbes through vaccination is the most effective method for protecting individuals against infection l This approach has led to the worldwide eradication of smallpox, the only disease that has been eliminated from civilization by human intervention 1 7 9 8 , E d w a r d J e n n e r noticed immunity bestowed to milkmaids-injected fluid from cowpox blister into skin of patients (orphan or prisonner) Introduction l The immune system prevents the growth of some tumors and participates in clearing dead cells and intiating tissue repair. l However, abnormal immune responses are the causes of many inflammatory diseases with serious morbidity and mortality. l The immune response is the major barrier to successful organ transplantation to treat organ failure. II. Organs and tissues of the immune system What are the major +ssues and organs of the immune system? The +ssue of immune system consist of: - the genera+ve lymphoid organs, in which T and B lymphocytes mature and become competent to respond to an9gens, - and the peripheral lymphoid organs, in which adapta9ve immune responses to microbes are ini9ated. Organs and tissues of the immune system The primary or genera+ve lymphoid organs in humans are, the bone marrow and thymus, since they are the sites of development and matura9on of the lymphocytes. Thymus gland Red bone marrow By defini9on, removal of these organs removes the capacity for immune cell genera+on. Secondary lymphoid organs (lymph nodes and spleen) are not essen9al for the genera9on of lymphocytes but have a key role in the matura+on of these cells and the development of immunity. Lymph nodes in par9cular anatomical sites are highly specialised, those surrounding the upper and lower respiratory tracts being known as the mucosa-associated lymphoid tissue (MALT) and those in the gut, the gut- associated lymphoid tissue (GALT) Organs and tissues of the immune system Lymph node Spleen III. Cells of the immune system