psychoneuroimmunology
mind and behaviour relate to brain function & immune system function
- fake flower induces allergic reaction
conditioned immunosuppression
related to learning theory.
US causes UR with no training.
pair CS and US, CS can cause UR, even tho not really related.
sugar water w decrese immune function drug.
conditioned immunoenhancement
immune system
- function?
- memory?
defend the body. detect self v non-self
- immunological memory. protect. vaccine - remembers virus & can better deal with it next time it comes about.
white blood cells
monocytes
lymphocytes - t-cell ,b-cell.
t-cell how it works
- macrophage ingests pathogen, sticks pieces on cell surface.
- t-cell binds to piece on macrophage.
- causes macrophage to release interleukn-1. = stimulates helper-t cell.
stimulated helpter-t releases interleukin-2 = acts on self to proliferate. - recruit cytotoxic t-cell to destroy foreign invader.
lymph nodes in body
filters lymph, cells gather there if they picked up antigen. look thru library of Ab to see if something will respond to it.
lymph nodes swell if looking for Ag to attack.
b- cell mechanism
macrophage takes in pathogen, present antigen. t-cell bind, release Il-1, t-cell release il-2. t-cell binds to b-cell - release b-cell growth factor = proliferation of b-cell.
b-cell produce anitbody, specific bind to antigen.
ab recruit what?
complement to destroy cells.
3 relevant Ig classes
IgG: crosses placenta - cross immunological protection to offspring
IgA: mucosal; used in stress studies
IgE: antibody of allergy and antiparasitic activty
3 features of acquired immunity
- specially target new pathogen ( proliferation doesnt happen unless exposed)
- takes time (few days to make Ab)
- repeated exposure enhances immune response
innate immunity
non-specific; macrophage engulfs
first point of entry = mucosal tissue.
capillaries loosen to get macrophages to pathogen
inflammation - fluid migration, damage to cardio system signals innate immune response.
effects of stress on immune system
suppress lymphocytes: reduce formation, suppress release
inhibit Ab formation
disrupt lymphocyte communication - IL1,2 b-cell GF.
inhibit innate immune response
glucocorticoid effect on immune system
shrunken thymus gland (age and sex hormones also decrease thymus gland)
remove lymphoctes from circulation
kill lymphocytes
shuts down HPA to inhibit immune function further.
why suppress the immune system during stress?
- short term?
- long term?
short term - actually increase immune system. lymphocytes better at releasing ILs, more sensitive to ILs. mediated by adrenaline.
long term stress = glucocorticoid action. immunosuppression.
why not enhance immune system during stress?
too hyperactive immune system = autoimmune disease.
autoimmune evidence:
- activate A but not Gc
- removal of adrenal glands produces Cushing’s
- spontaneous autoimmune due to malfunction of Gc response
autoimmune treatment
stress and autoimmune
- steroids can decrease immune activity. = autoimmune subsides
- short, frequent bursts of stress heighten cortisol without letting it fall = higher stress = higher adrenaline = extra high immune fxn.
chronic stress & disease risks.
social support and isolation. fewer social relationships = shorter life expectancy.
lower immune response to vaccines.
social support important for maintaining good health QUALITY not quantity
stress & common cold
fewer mucosal antibodies
more stress = 3x more likely of developing a cold.
chronic stress and disease risk AIDS - Gc effect on disease & progression. what is retrovirus? coping w denial
AIDS - more glucocorticoids = increased risk of HIV infection progressing to AIDS.
retrovirus - inserts into DNA, attacks when body is weak. CD4 count is 200/L w HIV; normal 1000/L
HIV + Gc = t-cell affected more quickly. stress hormones cause more quick infection.
coping w denial, little social support, social inhibition, stressors = succumb to diagnosis more when coping this way.
latent virus
dormant
herpes virus
replicate when immunocompromised
stress and cancer
- animal studies
- tumor growth thru immunity
stressful lab condition = tumor grows faster than in less stress condition
- natural killer cells decrease w stress. they function to prevent tumor/rogue cancer cell growth
stress effects thru non-immunity
tumors require energy, rapidly dividing. take energy from blood.
- call for angiogenesis (helped by glucocorticoids)
- absorbing glucose: increase tumor growth in animal that already has tumor
human studies of stress & cancer
no definitive link btw stress and cancer.
melatonin- protective against cancer.
maybe personality indirectly associated with cancer - low conscienciousness
stress and cancer progression
- coping mechanism
david spiegel study
fighting spirit vs depression & denial
- fighting = live over a year longer.
- david spiegel: treatment vs treatment + therapy = therapy lived 18 months longer.
- found this was probably due to greater compliance to treatment plan
