The Immune System
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Transcript of The Immune System
The Immune SystemThe key primary lymphoid organs of the immune system
are thymus and bone marrowSecondary lymphatic tissues such as spleen, tonsils, lymph
vessels, lymph nodes, adenoids, and skin.
Macrophage•Macrophage: A type of white blood
that ingests (takes in) foreign material. Macrophages are key players in the immune response to foreign invaders
such as infectious microorganisms .•Macrophages help destroy bacteria,
protozoa, and tumor cells. They also release substances that stimulate
other cells of the immune system .•And they are involved in antigen
presentation. To do this, they carry the antigen on their surface and present it
to a T cells.
Natural killer cells
•Can lyse and kill cancer and virus infected body cells
•They do not engulf the cells but inject chemicals called perforins that open up channels and disintegrate the nucleus.
Langerhans cells
Langerhans cells are dendritic cells in the skin. Skin is an important barrier to infection and it has been generally assumed that the Langerhans cells only serve to warn the immune system of skin
pathogens .
Dendritic cell•There are two cell types with similar
names but different functions. Cells of the dendritic cell (DC) lineage are bone marrow derived. In the skin they are
known as Langerhans Cells (LC).
• These cells efficiently process antigen but cannot present it to T cells. LC have been shown to pick up antigen in skin and carry it via afferent lymphatic vessels to lymph nodes. Dendritic cells in lymph are known as "veiled" cells. In lymph nodes the cells, now known as tissue dendritic cells or interdigitating cells, may efficiently present antigen if they encounter the right T cell. In fact these are the best APC...............far fewer DC are required to initiate an immune
response than any other APC .