Mast cells are major immune
cells in
allergy to secrete allergic mediators by a degranulation process and make and secrete inflammatory
lipids and
cytokines in response to
antigen stimulation. An
amino acid tryptophan regulates immune functions.
Tryptophan ameliorates inflammatory
colitis in which
mast cells are engaged. However, its effects on
mast cells remain to be solved. We investigated the effect of
tryptophan on
IgE-mediated allergic responses in the
mast cells and
mice.
IgE-mediated
passive cutaneous anaphylaxis (
PCA) in
mice were examined. Also
IgE-mediated
mast cell activation responses such as degranulation of stored granules and
secretion of inflammatory
lipid LTB₄ and
cytokines (TNF-α and
IL-4) were measured. Intraperitoneal
administration of
tryptophan suppressed
PCA in
mice. Also, in the cellular level
tryptophan inhibited
IgE-mediated
mast cell activation such as
IgE-mediated degranulation and the
production of LTB₄. Also, it inhibited
production of inflammatory
cytokines TNF-α and
IL-4. In summary,
tryptophan suppressed
IgE-mediated allergic activation in vivo and
in vitro.
Tryptophan supplementation is beneficial for
IgE-mediated
allergy.