Lecture exam #2 ch. 22 part 3 Flashcards
what is the most effective against intracellular microorganisms through the action of cytotoxic T cells?
Cell-mediated immunity
how does cytotoxic T cells identify abnormal or infected cells of the body in cell-mediated immunity?
through interactions with MHC molecules
what does cell-mediated immunity involve?
delayed hypersensitivity reactions and the control of tumors
what is anti-body-mediated immunity NOT effective against?
intracellular microorganisms (viruses, fungi, intracellular bacteria and parasites)
why is cell-mediated immunity effective against intracellular microorganisms?
because it destroys the cells in which the microogranisms are located
what do helper T-cells provide during cell-mediated immunity?
costimulation by releasing cytokines (interleukin-2)
what does the release of interleukin 2 cause?
stimulates activation and cell division of T cells
unlike B cells and macrophages what does helper T cells NOT do?
connect to T cells through MHC class II/antigen complexes or other surface molecules
what does an increased number of helper T cells result in?
greater stimulation of cytotoxic T cells
what happens when helper T cells are activated and stimulated during cell-mediated response?
they divide in the same fashion as in antibody-mediated response
what happens after T cells are activated by an antigen on the surface of a target cell?
they undergo a series of divisions to produce cytotoxic T cells and memory T cells
what are cytotoxic T cells responsible for?
cell-mediated immune response
what does memory T cells provide?
a secondary response and long-lasting immunity in the same fashion as memory B cells
what are the 2 main effects of cytotoxic T cells (2) (LP)
1) lyse cells
2) produce cytokines
what can stimulate cytotoxic T-cell activity? (3) (VTT)
1) virus-infected cells (virus antigens)
2) tumor cells (tumor antigens)
3) tissue transplants (foreign antigens)
what is the major method of lysis involve in cytotoxic t cells?
the protein perforin
what are the cytokines released by cytotoxic t cells responsible for?
phagocytosis and inflammation
order of antigen processing by MHC class I molecules (5) (PAMFS)
1) protein
2) antigens (protein fragments)
3) MHC class I molecule/ MHC class I/antigen complex
4) foreign antigen (MHC class I molecule)
5) self antigen (MHC class I molecule)
what does the last step of antigen processing by MHC molecule class I normally not stimulate?
cell destruction
order of antigen processing by MHC class II molecule (5) (FVVMP)
1) foreign antigen
2) vesicle containing MHC class II molecules
3) vesicle containing processed foreign antigens
4 ) MHC class II molecule (MHC class II/ antigen complex)
5) processed foreign antigen (MHC class II/antigen complex)
what does processed foreign antigen stimulate in antigen processing by MHC molecules class II?
immune cells
in costimulation by cytokines how are helper T cells first activated?
by a first signal and by costimulation
what is the first signal of costimulation by cytokines?
the binding of the MHC class II/antigen complex to th T-cell receptor
what is costimulation in costimulation by cytokines?
an additional signal (molecules released from another cell)
what is an example of costimulation by ctyokines?
macrophages release cytokines that bind to receptors on helper T cells resulting in costimulation
what are other costimulatory signals?
combining of surface molecules between cells (binding of B7 molecule of macrophage with a CD28 molecule of helper T cell)
in costimulation by surface molecules what does the CD4 molecule of helper T cell binding to macrophage’s MHC class II molecule help do?
hold the cells together
order of proliferation of helper T cells (5) (MPCID)
1) macrophage (antigen processed)
2) processed antigen (B7, CD4 and CD28)
3) costimulation (interleukin 1 receptor)
4) interleukin 2
5) divides into 2 daughter helper T cells
what does the first helper daughter T cell stimulated for?
to divide again
what does the 2nd helper T cell stimulate?
B cells or effector T cells
order of proliferation of helper B cells (7) (UBTCCBM)
1) unprocessed antigen binds to B cell receptor
2) B cells uses an MHC class II molecule to present the processed antigen to helper T cell
3) T cell receptor binds to MHC class II/antigen complex
4) costimulation of B cell by CD4 and other surface molecules
5) costimulation by interleukins (cytokines) released from helper T cells occur
6) B cell divides into 2 daughter b cells
7) many daughter b cells differentiate into plasma cells which produce antibodies
order of proliferation of cytotoxic t cells (5) (MTCID)
1) MHC class I molecule
2) T cell receptor
3) CD8 (costimulation)
4) interleukin-2 released from helper T cells
5) divides into 2 daughter T cells
2 types of T cells that T cells produce (CM)
1) cytotoxic T cells
2 )memory T cells
what does cytotoxic T cells do?
1) release cytokines
2) kill cells on contact
what does the release of cytokines by cytotoxic t cells do? (3) (PIA)
1) produce inflammation
2) initiate phagocytosis
3) activate T cells
what does killing cells on contact cause by cytotoxic t cells?
target cell lyses
when activated what do cytotoxic cells form?
many additional cytotoxic t cells as well as memory T cells
what does cytotoxic t cells release and what does that promote?
cytokines and it promotes the destruction of the antigen or cause the lysis of target cells
what are the memory T cells responsible for?
the secondary response
how is active immunity provided?
by the individual’s own immune system
how are antigens introduced with natural active immunity?
through natural exposure
how are antigens introduced with artificial active immunity?
deliberately in a vaccine
how is immunity provided with passive immunity?
it’s transferred from another person to an animal
what is happening with natural passive immunity?
antibodies from the mother are transfered to her child across the placenta or in milk
what is happening with artifical passive immunity?
antibodies produced by another person or an animal are injected
what does active and passive immunity lead to?
acquired adaptive immunity
how does HIV begin?
when a protein on the surface of the virus called gP120 binds to a CD4 molecule on the surface of the cell
when is a HIV infected person diagnosed with AIDS? (3) (HOK)
1) the helper T cells fount falls below 200
2) an opportunistic infection occurs
3) kaposi sarcoma develops
when symptoms occur within a few minutes of exposure to an antigen because antibodies are already present from prior exposure
hypersensitivity
a pure antibody preparation that is specific for only one antigen
monoclonal antibody
the endocytosis and destruction of particles by cells
phatocytosis
what are the cells call that destruct particles by endocytosis?
phagocytes
large phagocytic cells that are derived from monocytes
macrophages
when an antigen is deliberately introduced into a person’s body to stimulate the immune system
vaccination
similar to allergic reactions except that the immune system incorrectly treats self-antigens as foreign antigens
autoimmune disease
what are some examples of autoimmune diseases? (3) (RMM)
1) rheumatoid arthritis
2) multiple sclerosis
3) myasthenia gravis
a tissue graft from a donor of the same species as the recipient but not genetically identical
allograft
a tissue graft or organ transplant from a donor of a different species from the recipient
xenograft
a graft of tissue from one point to another of the same individual’s body
autograft
a graft of tissue between two indviduals who are genetically identical (monozyogtic twins)
isograft
a molecule formed from the integral binding of an antibody to a soluble antigen
antigen-antibody complex (immune complex)
