Psychoneuroimmunology
or
Psychoneuroendocrineimmunology
An interdisciplinary field that studies the reciprocal influences between the mind, nervous system, endocrine system, and the immune system.
Dates back to research by Adler in the 1970s – exemplified by the placebo effect
Psychoneuroendocrineimmunology
W.T.F.!
But how do these different system interact?
The Immune System
Threats to the Immune System
ANTIGENS
where leukocytes are produced
Different Types of Immunity
innate
acquired
response
fever
interferon release
NK cells
T-cells
B cells
NK cells
& produce
interleukins
White blood cells
kill bacteria
viruses &
fungi
Helper T cells �become activated �by interacting with antigen-presenting �cells, such as macrophages.
Helper T cells help activate cytotoxic T cells and macrophages
to attack infected
cells. They also
stimulate B cells
to secrete
antibodies.
(killer)
Suppressor T & B cells- in charge of slowing and stopping the immune response after the foreign substance is destroyed.
of the specific immune response
Cells in our body contain a molecule on their surface that is used to express that cell’s internal state. If infected by an antigen, this gets expressed by the molecule.
How does the brain “speak” to and influence the immune system?
neural axis
HPA
SAM
1. Neural axis
NE
Nerves of the sympathetic NS terminate on organs of the immune system. These nerves release norepinephrine, which binds to receptors on the immune organs.
2. SAM
The hypothalamus initiates neural impulses which travel along nerves that descend to stimulate the adrenal gland. The adrenals then release E and NE… which also bind to T cells and B cells
The hypothalamus secretes CRH…. which goes to the pituitary gland. The pituitary gland releases ACTH which travels down to the adrenal gland. The adrenals secrete glucocorticoids. Glucocorticoids bind to T cells and B cells.
2. HPA
How does the immune system “speak” to and influence the brain?
T cells, B cells, macrophages…. cannot pass through the Blood Brain Barrier
1. cytokines are actively transported � through the BBB�
2. cytokines find a weak spot in the BBB
capillary
Cytokines, chemical messengers of the immune system, are found in the brain.
Cytokines have definitive effects on the brain (modulate NE, serotonin, dopamine)
in the periphery�
the vagus nerve then sends neural
signals to the brain
Because the brain talks to the immune system…
Our experiences, thoughts and feelings are capable of affecting �the immune response.
Our immune system can be classically conditioned to�respond or not respond to a previously neutral stimulus
Anything that activates the autonomic NS is capable of altering immunity
What effect does stress have on the immune system?
Depends on the type of stressor, the type, amount, and timing of the stress hormones
released, the duration of the response, and degree of activation of the sympathetic NS. Also depends on age, sex, hormonal milieu etc…
Stress may have different effects on non-specific and specific immune responses
Stressor type
Physical
Psychological
Stress hormone
E, NE, cortisol,
Testosterone,
Oxytocin, vasopressin
Stress duration
Acute, chronic
sex
Age
Child
Adult
Elderly
Specific and
Non-specific immune responses
1, 152
In general,
stress inhibits the immune system
Stress increases activity in the HPA axis….
Glucocorticoids are released, which then inhibits immune system activity.
Behavioral Responses to HPA Activation: Stress vs Immune
Stress activation of SAM and HPA
Behavioral Responses to HPA Activation: Stress vs Immune
immune system activation release cytokines activates HPA
Life events vs. Daily Hassles and Uplifts
Which of these correlates most with
becoming sick??
BUT… this likely depends on the nature of the stressor,
one’s hormonal milieu, interpretation of the stressor and MANY other variables!