immune response Flashcards
what key words describe viruses
-non-living
-acellular
describe how HIV virus replicates
-attachment proteins bind to receptors on T lymphocyte
-viral RNA enters cell
-reverse transcriptase converts the RNA into DNA
-viral protein produced
-viral particles assembled and leave host cell
why are viruses considered non-living
-they require a host cell to live
explain the role of antigen presenting cells (APCs)
-macrophages display antigens on its surface
-enhances recognition by helper T cells, which cannot directly interface with pathogens in bodily fluid
give two differences between specific and non-specific immune responses
-non-specific, inflammation and phagocytosis, there is an immediate response
-specific response, B and T lymphocytes, time lag
what are the two types of cell response
-humoral
-cell-mediated
describe the events that occur during cell-mediated response
-COMPLEMENTARY helper T cells binds to antigens on APC
-release cytokines that stimulate:
-rapid mitosis of complementary helper T cell that become memory cells or activate humoral response
-rapid mitosis of cytotoxic T cells that secrete perforin that destroys infected cells
describe the events that occur during humoral response
-complementary helper T cell binds to foreign antigen on the APC
-causes rapid mitosis of complementary B lymphocytes from the release of cytokines
-B cells can differentiate into B plasma cells
-plasma cells secrete antibodies with complementary variable region to the antigen.
outline the structure of an antibody
-2 heavy chains and 2 light chains that are held together by disulfide bridges in quarternary structure
-binding site on variable region of light chain in tertiary structure, complementary to certain antigens
-constant region that doesn’t change
How do antibodies lead to the destruction of a pathogen
-formation of an antibody-antigen complex that results in agglutination which enhances phagocytosis
what are monoclonal antibodies
antibodies produces from a clone of a single B cell
what are memory cells
-memory T cells or memory B cells that remain in low amounts in the blood after primary immune response
-can divide very rapidly by mitosis if the same pathogen is encountered again
what causes antigen variability
-random genetic mutation causes change in base sequence
-results in different sequence of codons on mRNA
-different primary structure of antigen, so H bonds, disulfide and ionic bonds all form in different places in tertiary structure
-different shape of antigen
describe the types of immunity with an example
-active artificial, vaccination
-passive artificial, anti-venom
-active natural, immune response
-passive natural, antibodies across placenta
explain how a vaccination works
-dead/weakened version of pathogen injected
-triggers primary immune response
-memory cells are produced, so secondary response is rapid and produces higher concentrations of antibodies
-pathogen destroyed before symptoms present
