Use of bed rest and head-down tilt to simulate spaceflight-induce immune system changes.
Bed rest, both with and without head-down tilt, has been extensively used as an earth-bound analog to study physiologic effects mimicking those occurring in weightlessness during spaceflight. We have been able to show in six subjects that 4 weeks of head-down tilt bed rest induces a significant decrease in interleukin-2 secretion by PHA-stimulated T lymphocytes. Another study, lasting 113 days, with two subjects showed a decreased interleukin-2 receptor expression in PHA-stimulated peripheral blood mononuclear cells but a decreased interleukin-2 production in one subject only. Under the same conditions, interleukin-1 production was largely increased in both subjects. Several other immune parameters were also analyzed. Increased interleukin-1 production could contribute to bone mineral loss encountered during bed rest and decreased interleukin-2 secretion could play a role in the appearance of infectious diseases often observed during bed red.
Schmitt
D A
DA
Laboratoire d'Immunologie, Faculté de Médecine et CHU Rangueil, Toulouse, France.
Schaffar
L
L
Taylor
G R
GR
Loftin
K C
KC
Schneider
V S
VS
Koebel
A
A
Abbal
M
M
Sonnenfeld
G
G
Lewis
D E
DE
Reuben
J R
JR
Ferebee
R
R
D000917:Antibody Formation; D001510:Bed Rest / Q000009:adverse effects*; D018475:Head-Down Tilt / Q000009:adverse effects*; D006801:Humans; D007107:Immune System / Q000502:physiology*; D007136:Immunoglobulins / Q000097:blood; D007376:Interleukin-2 / Q000378:metabolism; D007958:Leukocyte Count; D008213:Lymphocyte Activation; D008297:Male; D012016:Reference Values; D013026:Space Flight; D013601:T-Lymphocytes / Q000276:immunology
D007136:Immunoglobulins; D007376:Interleukin-2