Immunology study guide for Quiz 1 Part 2 The Developmental Pathway Now we are taking a look at the various cells that are involved in immunity Specific and nonspecific innate immune system Note The B cells are Yellow and the T cells are Blue These colors will be consistent throughout the slides in areas that feature a concentration of one or the other type of lymphocyte Almost all of the cells involved in immunity originate in the bone marrow from the pluripotent hematopoietic stem cell Essentially we will divide the chart into two groups The blue group has to do with specific immune system mostly The red pink group has to do with the nonspecific immune system Blue Group Common lymphoid progenitor cell is the precursor for the various types of lymphocytes B cells Start out in the blood and typically migrate to lymphoid tissue where they may interact with antigen and get stimulated Once stimulated they develop into another cell that is an effector cell and is called a plasma cell The difference between a B cell and a plasma cell is that the B cell has the antibodies on the surface and the plasma cell is secreting the antibodies Involved in humoral immune system found in fluids T cells The cellular immune system is taken care of by T cells Called T cells because some of the progenitor cells migrate to the thymus and develop get differentiated in the thymus Before they get to the thymus they re just generic cells and not committed to anything T cells can be found in the blood they also migrate to the tissues the lymph nodes and other lymphoid tissues When they get stimulated by antigen they also become effector cells Their name doesn t change they are just called activated T cells as opposed to naive or resting T cells Activated T cells do not secrete their receptors they remain on the cell surface and the T cell goes around looking for antigen in or on infected cells using its surface receptors Natural Killer cells Not part of the specific immune system Will go into more detail later Pink Group Common Myeloid Progenitor differentiates into several different types of cells Can become a granulocyte macrophage precursor Differentiates into granulocytes and macrophages Granulocytes or polymorphonuclear leukocytes Neutrophils Eosinophile Basophile Mast cell precursor Travels through the blood as a precursor and once it gets into the Monocyte tissue it s a mast cell A macrophage precursor it travels through the blood as a it differentiates to a macrophage once it gets monocyte into the tissues Can become an immature dendritic cell There are actually several types that come from different sources but since they are so similar they are all called dendritic cells They leave the blood and enter the tissues and become mature dendritic cells once they interact with antigen Some actually come from lymphoid precursors and some from sources other Can become a megakaryocyte erythrocyte progenitor Erythroblast matures into an erythrocyte The megakaryocte which eventually becomes platelets The Cells of the Immune System and Their Roles Note Every cell has its own specific functions but if one happens to be first on the scene of an infection you need to be able to send for help and bring other cells and molecules in This will be covered in more detail later Macrophages and Dendritic cells Macrophages Are sort of like amoeba They crawl around and when they encounter something they phagocytize it In addition to their phagocytic activity they also have a bunch of antibacterial activities that will be discussed later All of this is involved in the nonspecific immune system They assist the specific immune system in that they help present antigen to B cells and T cells as antigen presenting cells or professional antigen presenting cells although they are not part of the specific immune system Dendritic cells have functions that overlap with those of the macrophage They also take up antigen and present antigen One difference is that they will pick up antigen in the tissues and actively transport it to your lymph nodes Neutrophils and Eosinophils Neutrophils Are granulocytes and have activities that are similar to the macrophage They live in the blood migrate to your tissues They have potent bactericidal mechanisms Unlike the macrophage they do not present antigen Eosinophils Are also granulocytes They are designed to kill parasites They grab onto the parasite and release granuals onto the surface of the parasite and the granuals are toxic to and will hopefully kill the parasite Unfortunately they play a role in allergies and asthma in that sometimes they get triggered by an allergen and release their toxic granuals to the point that allergy asthma symptoms are triggered Basophils and Mast cells Functionally basophils and mast cells are very similar Basophils In the blood Mast Cells In the tissues Both have large granuals Both have very strong anti parasite functions and both release granuals when triggered and both play a role in allergies and asthma Granuals contain histamine Natural Killer Cells Natural killer cells Develop from lymphoid linage but do not function like regular lymphocytes Have a lot of nonspecific functions They do have granuals in them but are not considered granulocytes Release granuals when stimulated and kill off cells typically your own cells that are infected can also kill tumor cells Help the specific immune system by looking for cells that are coated with antibodies If a cell is coated with antibodies there is probably something wrong The process by which a natural killer cell kills cells is called Antibody dependant Cell mediated Cytotoxicity ADCC This will probably be a test question Lymphocytes There are two major types of lymphocytes 1 B cells 2 T cells Responsible for the humoral immune system Produce Antibodies B Cells T Cells More complicated than B cells There are several different kinds of T cells T helper cells Th go around and help other lymphocytes to function properly They can help B cells develop into antibody producing plasma cells Can help other T cells to develop properly T regulatory cells Treg suppress the activity of various lymphocytes T cytotoxic cells Tc will kill off infected cells but unlike the Natural Killer cells they do it in an antigen specific way The Lymphatic System The cells of the immune system must have a way to circulate through the body they do not just float around at random Fluid dynamics The blood vessels are designed to be a little bit