BIOL1008 Lecture 21: Lecture 21
9 Jun 2018
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Lecture 21: Adaptive Immunity
Two main types of lymphocytes
- B lymphocytes (B cells)
Come from bone marrow
- T lymphocytes (T cells)
Originates in thymus
The thymus
- The prevailing dogma before 1960 was that the thymus was useless
- Jacques Miller is credited with the last person to still be alive to have identified the
function of a major human organ (thymus)
- He discovered that the thymus was in fact a generative lymphoid organ (gives rise for T
cells in our body)
- The thymus is where T cells learn how to be ‘good’ T cells
A good cell is a cell that doesn’t kill you
Types of adaptive immunity
- In humoral immunity, B lymphocytes secrete antibodies that eliminate extracellular
microbes (outside cells- only bind to microbes outside of cell)
2
Antibodies ineffective if microbe is inside
cell
- In cell-mediated immunity, different types of T
cells
Help phagocytes to destroy ingested
microbes
Kill infected cells
Two main types of T cells exist in the periphery
- Helper T cells (Th cells)
Help other cells of the immune response
Different types of Th cells exist with
specialized functions
Some helper T cells suppress or regulate
the immune response rather than
activate the immune response
- Cytotoxic T lymphocytes (CTLs)
Kill their target cells in a highly specific way
Get help from helper T cells
Play a key role in viral infections and anti-tumor immunity
- Peripheral tissues contain dendritic cells
- Dendritic cells (DC) are strategically located to
maximise chance of 1st encounter
- They have dendrites (arms)- extend their dendrites
into all different places
- Detect microbes
- Initiate adaptive immune response
They are the bridge between innate and adaptive
immunity
Document Summary
The prevailing dogma before 1960 was that the thymus was useless. Jacques miller is credited with the last person to still be alive to have identified the function of a major human organ (thymus) He discovered that the thymus was in fact a generative lymphoid organ (gives rise for t cells in our body) The thymus is where t cells learn how to be good" t cells. A good cell is a cell that doesn"t kill you. In humoral immunity, b lymphocytes secrete antibodies that eliminate extracellular microbes (outside cells- only bind to microbes outside of cell) Antibodies ineffective if microbe is inside cell. In cell-mediated immunity, different types of t cells. Two main types of t cells exist in the periphery. Help other cells of the immune response. Different types of th cells exist with specialized functions. Some helper t cells suppress or regulate the immune response rather than activate the immune response.
