Adaptive Immunity Flashcards
what are the characteristics of adaptive immunity
adapts throughout an organisms life, specialized cellular defenders, reaction to a specific antigen, retains “memory” of those antigens
what does our immune system’s memory rely on / how do they form
B and T cells / form during an infection and the memory can last for years
what are the two types of antigen presenting cells / how and what do antigen presenting cells do
Macrophage and Dendtritic cell / use membrane receptors to display fragments of pathogens that have been degraded by the phagocytes on cell surface
what are antigens
the small fragments of bacterial cells - peptides derived from proteins contained within foreign organisms - unique to the infectious agent and not found in the body
what are the two types of antigen presentation / what are the main differences between them
MHC I and MHC II / MHC I presents intracellular antigens and is found in all nucleated cells - MHC II presents extracellular antigens and is found on professional antigen presenting cells (Dendritic cells, Macrophages, Bcells)
how does MHC I presentation work / why is MHC I present in all cells of our body / what is another indication that a cell is infected
presents antigens from the cytosol - viruses get inside the cytosol, the cells digests proteins from the cytosol and loads those onto MHC proteins on surface of cell / because they are all susceptible to infection / a cell expressing nothing on their surface because viruses try to stop MHC production
how does MHC II presentation work / why are they only found on professional antigen presenting cells
presents antigens from outside the cell as phagocytes eat extracellular material and digest them - they then present from the digested material / because the cell has to be able to phagocotize a bacteria
where do antigen presenting cells migrate to / what is usually found in that tissue
lymphoid tissue / many of the bodies lymphocytes are found there
what are lymphocytes
the specialized cells of the adaptive immune system - the T-cells and B-cells
what are the antigens bound by when on MHC I / what are the antigens bound by when on MHC II
they are bound by CD8 T-cells / they are bound by CD4 T-cells
what does APC do / what does the uniqueness of a T-cell do
looks for T-cell with a receptor that binds the antigen a they all hare unique / allows them to bind with a specific antigen
what happens when a CD8 T cell is activated
it divides many times into two different things - Memory cytotoxic T-cells (they stay in the Lymphoid tissue) and Cytotoxic T cells (they enter the blood stream to find cells with the antigen)
what do the Cytotoxic T-cells (CD8) do
they circulate the blood stream to find infected cells that show the antigen - instructs that cell to undergo cell death (apoptosis)
what happens when CD4 T-cells are activated / what happens to those cells after being bound
they bind naiive B cells / they go look for the same antigen and come back to the CD4 T-cells to confirm it is the correct antigen
what does the variable region in the B-cell receptor do / what happens when a B-cell is bound to a matching antigen
results in the ability to bind unique antigens - when they are bound they activate / they internalize it and present it on MHC II similar to macrophage and dendritic cells
