Biology Reference
In-Depth Information
13
Increased Type 1 Helper
T Cell Functions and Reward
Stimulation
Noriyuki Kawamura
1
, Hirofumi Iimori
2
and Marcus Wenner
1
1
Section of Psychosomatic Disorder Research, National Institute of
Mental Health, National Center of Neurology and Psychiatry, Tokyo,
Japan,
2
Iimori Clinic
13.1 Introduction: Psychological Variables Do Correlate
with Immune Alterations
A recent meta-analytic study showed that psychological stress does correlate with
immunosuppression
[1]
. This report covers more than 300 empirical articles describ-
ing a relationship between psychological stress and parameters of the immune system
in human participants. Acute stressors were associated with potentially adaptive up-
regulation of some parameters of natural immunity and down-regulation of some func-
tions of specific immunity. Brief naturalistic stressors (such as school examinations)
tended to suppress cellular immunity while preserving humoral immunity. Chronic
stressors were associated with suppression of both cellular and humoral responses.
Effects of event sequences varied according to the kind of event (e.g., trauma ver-
sus loss). Subjective reports of stress generally did not associate with immune sys-
tem changes. Cell populations that were very sensitive to stress included natural killer
(NK) cells and T cells. In addition, NK cytotoxicity, type 1 T helper (Th1) cell func-
tion, and T-cell proliferation to mitogen were all sensitive to various type of stresses.
In contrast, some effective psychosocial interventions succeeded in augmenting
immune function, especially of those immune cells that were sensitive to stress
[2-5]
.
13.2 Neural Regulation of Immunity
The meta-analytical findings suggest that immune function is regulated by the central
nervous system (CNS). In terms of immune suppression, brain destruction studies
have shown that hypothalamic areas are relevant to immune modulation
[6,7]
. Thus,
we performed several electrical brain stimulation studies
[8-10]
. Because we were
interested in the augmentation of immunity, we focused on electrical stimulation of
