Coming soon....Blood Family Tree - Best viewed printed in color at best quality in landscape format. This is a diagram I created with input from several different sources. It attempts to show lineage of cells back to stem cells and it shows the different paths that can be taken for creation of dendirtic cells.
Granulocytes - Cells that contain granules. These granules are released in the presence of foreign materials. The contents of the granules help dissolve the foreign material. Examples: Mast Cells, Basophils, Eosinophils and Neutrophils.
Phagocytes - Cells that encapsulate foreign materials, dissolve them with enzymes and then expel the debris. Professional eaters. Phagocytosis is a very important defense of the non-specific or innate immune system. Examples: Neutrophils, Monocytes, Macrophages and Dendritic Cells.
Antigen Presenting Cells - Until recently their function was not well understood. This process is the key function of Langerhans Cell (Epidermal Dendritic Cells) and Dermal Dendritic Cells. Dendritic cells and some other cells such as Macrophages and B-Cells present antigens to T-Cells (a special kind of lymphocyte) and then T-Cells go on the attack. Antigen Presenting cells are now understood to be key to starting the specific or adaptive immune system response. They are the key cells that alert lymphocytes to invaders in the body.
Macrophages - Macrophages are professional phagocytes (or cells that eat antigens and other foreign material). They also have the ability to present antigens to other cells (see antigen presenting cells) but this is not their main job. Click here for a montage of images of macrophages I created from images found on the internet. Macrophages are derived from monocytes. When a monocyte leaves the blood stream and migrates into tissue it matures into a macrophage, the specific type depends on its location, the chemicals and other cells it encounters. Monocytes may also mature into dendritic cells, but this is not well understood.
Dendritic Cells - Click here for a montage of images of dendritic cells I created from images found on the internet. They are called dendirtic cells because of their dendrite like arms that are used to reach between other cells for increased contact area. Dendirtic cells are closely related to monocyte-macrophage cells (also called mononuclear cells). They are white blood cells. It is not certain if these cells are derived from monocytes or if they come from a much earlier precursor. Dendritic cells main function is to present antigens to lymphocytes (specifically Helper T-cells) to get the adaptive immune response started.
Langerhans Cell - see Epidermal Dendritic Cell
Epidermal Dendritic Cell - Also called the Langerhans Cell after its early discoverer. This particular dendirtic cell resides in the epidermis, the outer most layer of skin. It is a professional antigen presenting cell. Its job is to eat foreign substances (via phagocytosis) digest the antigens and then display part of the antigen on the cell surface. The dendritic cell then travels to the lymph system to alert Helper T-Cells that there is a potential invader. The Helper T-Cells then stimulate the production of Cytoxic or Killer T-Cells via chemicals called cytoxins. The Cytoxic T-Cells then go to the site of inflammation (directed by chemokines) and
attack. You actually have about 500 Langerhans cells per square inch of normal skin. These cells are Phagocytes (they ingest foreign substances), but they do this as a means for their main job - antigen presentation to other cells, phagocytosis is not their main job or purpose (Macrophages fill that roll). A feature found in the Langerhans cells that is not found in other dendritic cells or other cells for that matter is the Birbeck granule - the function of this cell feature is not understood. Dysfunction of this cell or of the processes just discussed are suspected as the cause of Langerhans Cell Histiocytosis. The evidence of this is that cells found in the lesions associated with LCH contain Birbeck granules and stain the same as Langerhans cells for S100 and CD1a. There is some evidence that the cells involved are not normal - they look different from the normal cells found in the epidermis. Perhaps they change because they are 'activated' or perhaps they are mutated in some manner.
Dermal Dendritic Cell - These cells are found in the dermis, the layer of skin just under the epidermis. These cells are not nearly as well know as Epidermal Dendritic Cells (Langerhans Cells). They were considered something of a curiosity until recently. In recent years, these cells have been looked at as a potential way to introduce vaccines for things like AIDS and cancer. This is referred to as immunotherapy. If you could get a dendirtic cells to take up a given antigen, then you may be able to stimulate the immune system via dendritic cells to attack virus infected or cancerous tumor cells. Much research is being done here. Dysfunction of this cell or of the antigen presentation process just discussed are suspected as the cause of a kind of histiocytosis called Juvenile Xanthogranuloma. Evidence that dermal dendrocytes are involved in JXG is that normal dermal dendrocytes and biopsy samples from JXG lesions both stain positive for Factor XIIIa, but this does not prove that JXG comes from dermal dendrocytes or that dermal dendrocytes are involved.
Other Dendritic Cells -
Spindle Cells -
Tuton Giant Cells -
Foreign body Giant Cells -
Epitheliod Cells -
Foamy Cells -
Mixed Inflammatory Infiltrate -
Fibroblasts -Mast Cells -
Eosinophils -
Neutrophils -
Basinophils -
Lymphocytes -
T-Lymphocytes (T-Cells) -
B-Lymphocytes (B-Cells) -
Cytokines -
Antigens -
Key Cells
Giant Cells
Epitheliod Cells
Langerhans Giant Cells
Langerhans Cells
Foreign-body Giant CellsMonocytes
Macrophages
Dendritic Cells
T-Cells
Cytokine
