5Specific immune response Boardworks AS BiologyImmunologySpecific immune responseThe specific or adaptive immune response can target a specific pathogen, although it is slower to act than the non-specific response.It features two main types of response to pathogens:the humoral or antibody-mediated response targets pathogens in body fluids with antibodies.the cellular or cell-mediated response involves highly-specialized cells that target pathogens inside cells.Photo credit: CDC / Dr F GilbertThis micrograph of a fixed blood smear revealed a polymorphonuclear leukocyte (PMN) and a number of red blood cells (RBCs); Mag. 1000x.Polymorphonuclear leukocyte are also known as granulocytes, due to the presence of granules of membrane-bound enzymes involved in digesting endocytosed particles. The three types of granulocytes are neutrophils, eosinophils and basophils.Teacher notesThe specific immune response is only found in vertebrates.The specific/adaptive immune response can also be called the acquired immune response.
7Boardworks AS Biology Immunology What are lymphocytes?Lymphocytes are a type of white blood cell (leucocyte) found in the blood and lymph nodes.Lymphocytes recognise antigen molecules on the surface of pathogens, and co-ordinate the immune response against that pathogen.Photo credit: Steve Gschmeissner / Science Photo LibraryColoured transmission electron micrograph of a plasma cell. Plasma cells are mature B lymphocytes (white blood cells) that produce and secrete antibodies during an immune response. The cell's nucleus (black) contains dense chromatin (green), a complex of DNA (deoxyribonucleic acid) and proteins. In the cell's cytoplasm (green) is an extensive network of rough endoplasmic reticulum (RER, dark lines). RER manufactures, modifies and transports proteins, in this case antibodies. There are also a number of mitochondria (blue, oval) in the cytoplasm, which provide the cell with energy. Magnification: x4000 when printed 10 centimetres wide.Teacher notesSee the table (below) for the major categories of leukocytes.Antigens are usually proteins or glycoproteins. Lymphocytes will also produce an immune response against transplanted cells and even cancer cells, which they detect as foreign.Collectively, lymphocytes can recognize millions of different antigens, due to the large variation of lymphocytes produced.Granulocytes (polymorphonuclear leukocytes)Agranulocytes (mononuclear leukocytes)neutrophillymphocytebasophilmacrophageeosinophilmonocyte
8Lymphocytes B Cells T Cells Made in Bone Marrow Travel in Blood and LymphProduce antibodies (immunoglobulins)Have membrane bound receptors identical to the antibodies they produce called IgMs100 Million types of B cells formed in developing embryo, all with different IgMsMade in Bone Marrow, but mature in Thymus GlandDisplay T Cell receptors on their cell surface membrane.2 main typesT Helper cells – Stimulate the production of antibodies against antigens on pathogensT Killer Cells – Produce chemicals to destroy pathogens
9Different types of lymphocytes Boardworks AS BiologyImmunologyDifferent types of lymphocytesTeacher notesSee the ‘Cell Division’ presentation for more information about stem cells.
10Humoral immune response Boardworks AS BiologyImmunologyHumoral immune responseTeacher notesPlasma cells produce a single type of antigen-specific antibody at a rate of about 2,000 antibodies per second. The antibodies then circulate through bodily fluids, attacking the triggering antigen.Antibodies are removed from the bloodstream by the kidneys once the infection has been overcome.
11Boardworks AS Biology Immunology Effector mechanismsBoardworks AS BiologyImmunology
12Homework Read and highlight White Blood Cells information sheet Find out what is meant by the Major Histocompatibility Complex (MHC)