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
what happens to the B cells when they confirm their antigen with CD4 T-cells
they become activated and divide many times into memory B-cells that stay in the lymphoid tissue and plasma cells that move into the blood stream
what do the plasma cells do in the blood stream / what is an antibody
they secrete antibodies / disables pathogens and tags them for removal
what does the two step authentication of B-cells and antigens do
helps prevent auto immunity
what does an antibody look like / what do antibodies contain
it is the soluble form of the B-cell receptor that is secreted in high quantities by plasma cells / they contain an antigen binding region (Fab) and a constant region (Fc)
what are the functions of antibodies
COIN - Crosslinking, Opsonization, Immobilization, Neutralization
what does crosslinking do
increases phagocytosis by binding both antigen binding sites to create a little colony - make phagocytosis more efficient
what does Opsonization do
increases phagotcytosis by coating a bacteria in antibody - because anitbodies are a good sign for something to be eaten
what does immobilization to / what does neutralization do
decreases motility/adherance by crosslinking flagella or binding the pilus / inactivates virulence factors by binding the toxin with antibodies to prevent cellular reception
what does the TDaP Vaccine do
gives antibodies to the diptheria toxin which causes cell death
what is humoral immunity / what is cellular immunity
the extracellular infection that uses MHC II / intracellular infection that uses MHC I
what is the difference between primary and secondary antibody responses
secondary exposure to an antigen through infection or vaccination, memory cells rapidly respond and produce protection very quickly compared to the primary response
