what are the two main branches of specific immune defenses?
1. antibody- mediated immunity
2. cell- mediated immunity
what do both branches have in common?
they are antigen- specific meaning they are antibody generating
what is an antigen?
any compound, usually large and complex, that is foreign/non-self and stimulates both branches and stimulates both branches of specific immune system
what are the chemical structures of antigens?
any compound as long as it is foreign usually large and complex such as proteins, nucleic acids, lipids, and carbs
which type of antigen is the most likely to be structurally complex?
proteins, they create the best response from our defenses
what are the two types of antigens?
1. cell- bounded (attached to pathogen)
2. soluble/free- floating (released from pathogen)
what is a cell bound antigen?
compunds that are foreign and are attached to surface of the pathogen such as part of the cell wall, flagella, pili, etc
what are soluble antigens?
compunds that are seperated from the pathogen such as endotoxins, fragments of lysed pathogens
what are extracellular antigens?
antigens that are not able to enter host cells, circulate in blood, lymphatic system, interstitial spaces
why can a virus be both an intracellular and extracellular antigen?
the are extracellular before they enter a host cell
does the specific immune system go after one unique pathogen or toxin?
no, one pathogen may have many antigens
what is an epitope?
different regions of the antigen that each stimulate an independent specific immune response
what does it mean by immune system cells are antigen- specific?
cells of specific immune system are only able to recognize one epitope of one antigen
does the specific immune system respond to all antigens, regardless of their chemical structure, origin, or location?
when can a receptor bind to one epitope of one antigen in antibody mediated immunity?
once mature B cells display their 10K- 100K receptors on surface
where do mature B cells circulate?
blood, lymph, migrate to lymph nodes, spleen, and wait for antigen to arrive
what happens when an antigen arrives during antibody- mediated immunity?
it binds to receptors causing activation of B cell
what are plasma cells?
they are the most abundant and make and secrete antibodies 2000/sec for 4-5 days than they die
what are memory B cells?
long-lived, remain in body and wait for same antigen to return in the future it it does it will mount a stronger, faster, longer lasting response
what are the four things antibodies do?
4. lysis by complement fixation
what is neutralization?
antibody coat the surface of antigens so that they are unable to interact-with host cells, they are inactivated
what does neutralization, precipitation, and agglutination all have in common?
they all opsonize the antigen and enhance phagocytosis
what are antobodies not capable of doing?
entering host cells, so they are only effective against extracellular antigens
what is double recognition?
receptors simultaneousley recognize:
1. one epitope of one antigen
2. the host cell MHC ("self")
what are the four types of clone cells for T lymphocytes?
1. cytotoxic T cell
2. Helper T cell
3. Suppressor T cell
4. Memory T cell
how does a cytotoxic T cell kill the host?
1. secrete perforins causing lysis
2. secrete lymphotoxins causing degredation of host DNA
3. secrete tumor necrosis which causing apoptosis (cell suicide)
what type of T cell inhibits further actions of T and B cells once antigen/pathogen is gone?
supressor T cells