why is adaptive immune response important?
- protects us from many infections
- has memory so we are not infected by the same pathogen a 2nd time (this is why vaccinations work)
Adaptive immune response is the 2nd level of immunity. what does it involve?
- it involves lympcytes
- it is a response to specific antigens
- it is exraordinarily specific
- it can adapt to any infection
- it has memory (life long immunity)
what are the 2 types of respnses
- innate- prerequistie for adaptive immune response
- adaptive immune response (2 types)
- -humoral- production of antibodies
- -cellular- killing and regulation og infected cells
define humoral and cellular responses.
- carried out by B lymphocytes
- Responsible for production of antibodies
- activation of B cells usually requires help from T cells
- some B cells proliferate and differentiate into plasama cells (produce massive amounts antibody)
- Some B cells become memory cells
- carried out by T lymphocytes (cytotoxic T and helper T cells)
- responsible for killing and regulation of infected cells
- T cells that have not seen antigen are considered naive, but after encountering antigen, both T cell types become armed effector T cells
where is the lymphatic system?
- cover the entire body
- lymphocytes and lymphoid structures
- adaptive immune response is associated w/ it
what is the function of dendritic cells?
- most important cells in the adaptive immune response
- -have enormous surface areas- grabs antigen
- -take up and process antigens
- -present antigens to T cells
what is a clonal selection? fig 16.7
- which some lymphocytes are destroyed and others are allowed to mature. this selection process takes place in the bone marrow for B cells and in thymus for T cells
- how the immune system responds to infection
- takes place in the bone marrow for B cells and in the thymus for T cells
- lymphocytes that remain after clnal deletion maure
- each is specific for nonself antigen
- if an antigen is encountered, the lymphocye is activate (begins to divide and proliferate. It forms a clone of cells specific for one antigen)
- lymphocytes that never encouter antigen eventually die
what are the 3 important points about clonal selection?
- it generates a vast # of different antigen receptors
- each receptor is specific for a different antigen
- all progeny of that lymphocyte will have the exact same receptor
what do lymphid precursos T and B cells give rise to?
- T cells- Cytotoxic (Tc) and Helper T cells
- B cells- differentiate into plasma cells
what are the 2 types of helper T cells? what do they activate?
- 2 types of helper T cells-
- Activate the B cells and macrophages
- T cells are naive until they encouter antigens (co-stimulatory signals must be present)
when B cells and T cells mature, they acuire specific antigen receptors...
- B cell receptor is an immunoglobulin molecule (2 antigen binding sites)
- T cell receptor is similar to Ig (only 1 antigen binding site)
where do B and T cells originate form? where do T cells mature? Where do B cells mature? then what do they do?
- B and T cells originate in bone marrow
- T cells mature in the thymus gland (thymus atrophies at puberty, T cells are long lived, maturation requires specific signals)
- B cells mature int he bone marrow
- when mature, both circulate through the blood and tissues looking for antigens
- maturation requires specific signals
lymphoid tissues, B cells. Tell me when B cells die?
- most of them die when they reach the peripheral tissue
- they are constanty replaced and therefore the # remains constant
what are the 3 functions of antibodies?
- neutralization: antibodies neutralize toxins and virsuses and also prevent bacterial attachment ("staying in" requirment for infection)
- opsonization: antibodies facilitate the uptake of pathogens by phagocytic cells
- complement activation system: antibodies activate the classical pathway of the complement system
name the 5 antibody isotypes?
IgM, IgG, IgA, IgE, IgD
- first antibody to be produced in a humoral response
- pentamer structure
- usually found in blood
- excellent activator of the complement system
- primary response to bloodborne pahtogens
- found in pleural spaces (protects enviro pathogens)
what is IgA?
- principle antivody in secretions
- found in respiratory and digestive tract
- it is not very effective in activating the complement system
- found in colostrum (transfered from mom to child. protects against newly encountered bacteria)
what is IgG?
- principal isotope in the blood and exracllular fluid
- very effective for opsionization and activation of complement
- newborns recieve (can cross the placenta)
what is IgE?
- found in low levles in the blood and extracellular fluids
- binds tightly to mast cells just below the skin and mucosa
- it is also found along the blood vessels in connective tissue
- after antigen binding, powerful chemical mediators are released (causing coughing, sneezing, vomitting)
what is IgD?
- found in very small amounts in the blood
- it is found on the surface of B cells
- has no known function in serum
- it is involved as an early antigen receptor
Tell me about T cell response
- cellular immune cell response is generated by T cells (cytotoxic and helper T cells)
- T cells that have not seen antigen are considered to be naive
- after encountering antigen, both types become armed effector T cells
what are the 3 classes of armed effector T cells
- Th1 helper- provide activation signals for macrophage
- Th2 helper
- most of these move into the blood when they are activated
- cytotoxins are released by cytotoxic T cells
- cytokines are released by helper T cells
what is one of the most improtant properties of adaptive immune response? what form can it be seen in? what is the memory due to? what due interlukins help do?
- immunological memory is most important
- seen in both T and B cells and is produced after infection or vacination
- memory is due to persistent population
- Interleukins help maintain the memory T cell pop
when does innate and adaptive response take place?
- innate= early stages of infection
- adaptive= few days after 1st exposure to antigen
- once the pathogen is estab. only adaptive can rid of it
explain the immunity to infection
explain adaptive response