BIOCHEMICAL
Vol. 168, No. 2, 1990
AND BIOPHYSICAL RESEARCH COMMUNICATIONS Pages 396-401
April 30. 1990
ImmnoreactiveGrowthHonmne
(GH) Secretion byEIunranLyr@ocybes:
AugrssntedRe1eas.e Naoki
Hattori,
Akira
bymenous
Shimatsu,
Masahiko
GH
Sugita,
Shunichi
Kumagai,
andHirooImura Second
Received
Division,
Kyoto
University
February
26,
Department Faculty
of Internal
of Medicine,
Medicine,
Kyoto
606,
Japan
1990
Peripheral blood mononuclear cells (PBMCs) from normal adults secreted small amounts of human growth hormone (GH;0.2-0.6 pg/105 cells/7 days culture) as measured by a highly sensitive enzyme immunoassay. Stimulation of PBMCs with phytohemagglutinin (PHA) consistently showed a 4-6 fold increase in GH secretion. Transformed B-lymphocytes by Epstein-Barr virus also secreted GH (O-8-4.8 pg/5 x lo* cells/7 days culture). GH secreted by lymphocytes comigrated with pituitary GH on an Ultrogel AcA44 column. Addition of GH during the culture augmented endogenous GH secretion from PHA-stimulated PBMCs. GH-releasing hormone and a somatostatin analogue, SMS 201-995, did not affect GH secretion from non-stimulated and PHAstimulated PBMCs. These findings suggest that both T and B lymphocytes secrete immunoreactive GH in a different manner from that in the anterior pituitary. o 1990 Academic Pres*, Inc. Recent tween have It
studies
the
immunoregulatory
has been
ACTH,
shown
endorphin
(GH)-related phocytes that
Very
by
bioactivity, describe
TSH (3)
a highly
were
recently,
quantitative sensitive
communication
systems
cytokines produce
also
is
et
similar
and molecular analysis enzyme
hormones
have
neuroendocrine
effects.
(4).
immunoassay
have secrete
pituitary
weight.
of GH secretion (EIA)
such as hormone
mitogen-stimulated
(6) and
to
peptides
Prolactin/growth in
al.
synthesize
be-
Neuroendocrine
detected
Weigent can
exists
(1).
neuroendocrine
and prolactin
leukocytes
antigenecity, the
and
lymphocytes
lymphocytes
bidirectional
immune
effects
mRNA species (5).
that and
that (2),
mononuclear
produced
using
indicate
neuroendocrine
provided GH in GH in
In the present
lymevidence vitro.
GH
terms
of
study,
we
by T and B lymphocytes for
GH (7).
Venous blood was taken after an overnight fast from normal adult volunteers. Plasma GH levels determined by EIA at the time of blood withdrawal ranged from 0.18-l-5 ug/L. Peripheral blood mononuclear cells (PBMCS) were isolated by standard Ficoll-Hypaque gradient centrifugation (8) and suspended in culture medium (RPM1 1640) containing 10% fetal calf serum (Filtron, Australia) and antibiotics. PBMCs (1 x 10'cells in 200 pL) ooo6-291x.90 $1.50 Copyright 6 1990 by Academic Press, Inc. All rights of reproduction in any form reserved.
396
Vol.
168, No. 2, 1990
BlOCHEMlCAL
AND BIOPHYSKAL
RESEARCH COMMUNICATIONS
were incubated in triplicate at 37OC in 5% COz with the following additives: 0.2% phytohemagglutinin (PHA;Difco, Detroit, MI), 1% pokeweed mitogen (PWM;Sigma, St. Louis, MO), 20 mg/L lipopolysaccharide (LPS; Difco, Detroit, MI), human pituitary GH (Sumitomo Pharmaceuticals, Tokyo, Japan), GH-releasing hormone (GHRH;Peptide Institute, Osaka, Japan), a somatostatin analogue (SMS 201-995;Sandos Pharmaceuticals, Bazel, Switzerland). After incubation, the cells were removed by centrifugation and the culture supernatant was used for the assay. Epstein Barr (EB) virus-transformed B cell lines were established from normal subjects, as previously described (9). Gel chromatography The culture supernatant of PHA-stimulated T cells or EB virustransformed B cells was concentrated lo-30 fold with polyethylene glycol. The concentrated samples (0.5-1.0 mL) or GH standards in culture medium were applied onto an Ultrogel AcA44 column (0.9 x 70 cm) and eluted with 0.01 mol,/L phosphate buffer containing 0.1 mol/L NaCl, 0.1% NaNa, and 0.1% bovine serum albumin at 4'C. The fractions of 0.8 mL were collected and assayed for GH. The column was calibrated by markers with various molecular weights. Assays GH was measured by a highly sensitive enzyme immunoassay (EIA) as previously described (6). In brief, samples (100 pL) were incubated with anti-GH IgG-coated polystyrene balls at 37OC for 6h. After washing with saline, the polystyrene balls were incubated with anti-GH Fab' peroxidase conjugate at 4 'C or 16h and at 20°C for 6h. After washing with saline, peroxidase activity bound to the balls was assayed using a fluorescence method. A spectrofluorophotometer (Shimadzu RF-540, Kyoto, Japan) was used to measure the fluorescence intensity. The detection limit was 1 x lO"ug/L. The intraand inter-assay coefficients of variation were 6.0% and 8.6%, respectively. Statistical analysis The data were expressed as means?SEM. Student's t-test analysis of variance in combination with Duncan's new multiple were used for statistical analysis as appropriate.
and one way range test
RESULTS PBMCs (1 x 10' of
immunoreactive
Stimulation
of PBMCs with
increased not
pg/well)
7 days
into
the
two fold, EB virus
for
7 days
a T-cell
the
time-course
while
small
as shown mitogen,
a B-cell
addition
transformed
secreted
secreted
media,
PWM cl%),
in GH secretion. about
GH secretion.
cultured
for
PHA (0.0125-0.2%),
increase
GH secretion
stimulate
cultured
GH (0.2-0.6
a dose-related
/well)
cells/well)
in
Fig.1.
resulted mitogen,
in also
of LPS (20 mg/L)
B cell
variable
amounts
lines
amounts
did
(5 x 10'cells
of
GH (0.8-4.8
pg/well). Fig.2a
shows
PHA-stimulated incubation. incubation
lymphocytes. Small for
amounts from
day
to
and continued
stimulated
GH secretion
GH secretion not
unchanged
PBMCs was increase
was dependent
the
were
during
9 days
9th
on the
397
non-stimulated
immediately
pg/well)
stimulated
till
from
detected
of GH (0.2-0.6
6h and remained
PHA. GH secretion
of GH was
secreted
day.
As shown
number
the
after
the
of culture
by PHA after
the
and
after
without 3rd
in
Fig.Zb,
of cultured
cells.
to
5th PHA-
Vol. 168, No. 2, 1990
BIOCHEMICAL
PHA
stimulated
PWM LPS
AND BIOPHYSICAL RESEARCH COMMUNICATIONS
EB-V transformed B cell lines
Time
xl05cellshel
Figure 1. Secretion of immunoreactive GH from non-stimulated, mitogens lymphocytes, and three EB virus-transformed B (PHA, PWM, LPSJ-stimulated cell lines during the culture for 7 days. Figure 2. (a) Time course of GH secretion from non-stimulated (triangle) and PHA-stimulated (circle) lymphocytes in 2 normal subjects. The number of cells was 1 x lo5 /well. (b) The relationship of GH secretion from PHAstimulated lymphocytes with the cell numbers in the 7 days culture. Mean?SE of GH levels in triplicate wells are shown. To investigate 100
x lo-'
with
pq/L)
GH secretion
was added
PBMCs. GH was stable
calculated
the
GH from
the
creased
recovered
(Table
exogenous affect
1).
in
not
curve
curve
position
of were
GH (lo-
and incubated
in media
without
cells
(mean recovery:99.3%).
of secreted
GH by subtracting
GH levels.
The
from
addition
PHA-stimulated numbers
of
not
in
changed
We
of added
(10“
in-
a dose-related
by the
SMS 201-995
non-stimulated
amounts
I days
GH significantly
lymphocytes
were
M) and/or
the
for
addition
of
-10s6 M) did
and PHA-stimulated
not
lymphocytes
shown).
A dilution standard
exogenous
media
cell
GH secretion
regulated,
culture
from The
was
the
GR. GHRH (lo- 'O-10*'
the
(data
amounts
GH secretion
manner
forms
whether
of
of
GH produced
GH (Fiq.3).
22K GH on gel also
Table
observed
1. Effects
by lymphocytes
Immunoreactive chromatography
as in the of exogenous
0 10
(Fiq.4).
Minor
case of pituitary
GH.
Secreted non-stimulated 0.2 kO.1
50
100 Values show mean rSE of secreted * PCO.02 vs. secreted GH from in the absence of exogenous ** PCO.01 vs. secreted GH from in the absence of exogenous ***p