Spaceflight effects on T lymphocyte distribution, function and gene expression.
The immune system is highly sensitive to stressors present during spaceflight. The major emphasis of this study was on the T lymphocytes in C57BL/6NTac mice after return from a 13-day space shuttle mission (STS-118). Spleens and thymuses from flight animals (FLT) and ground controls similarly housed in animal enclosure modules (AEM) were evaluated within 3-6 h after landing. Phytohemagglutinin-induced splenocyte DNA synthesis was significantly reduced in FLT mice when based on both counts per minute and stimulation indexes (P < 0.05). Flow cytometry showed that CD3(+) T and CD19(+) B cell counts were low in spleens from the FLT group, whereas the number of NK1.1(+) natural killer (NK) cells was increased (P < 0.01 for all three populations vs. AEM). The numerical changes resulted in a low percentage of T cells and high percentage of NK cells in FLT animals (P < 0.05). After activation of spleen cells with anti-CD3 monoclonal antibody, interleukin-2 (IL-2) was decreased, but IL-10, interferon-gamma, and macrophage inflammatory protein-1alpha were increased in FLT mice (P < 0.05). Analysis of cancer-related genes in the thymus showed that the expression of 30 of 84 genes was significantly affected by flight (P < 0.05). Genes that differed from AEM controls by at least 1.5-fold were Birc5, Figf, Grb2, and Tert (upregulated) and Fos, Ifnb1, Itgb3, Mmp9, Myc, Pdgfb, S100a4, Thbs, and Tnf (downregulated). Collectively, the data show that T cell distribution, function, and gene expression are significantly modified shortly after return from the spaceflight environment.
Gridley
Daila S
DS
Department of Radiation Medicine, Loma Linda University, Loma Linda, CA 92354, USA. dgridley@dominion.llumc.edu
Slater
James M
JM
Luo-Owen
Xian
X
Rizvi
Asma
A
Chapes
Stephen K
SK
Stodieck
Louis S
LS
Ferguson
Virginia L
VL
Pecaut
Michael J
MJ
D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology; D016207:Cytokines / Q000235:genetics / Q000378:metabolism*; D004261:DNA Replication; D005260:Female; D005434:Flow Cytometry; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D007694:Killer Cells, Natural / Q000276:immunology; D008213:Lymphocyte Activation / Q000235:genetics; D018655:Lymphocyte Count; D051379:Mice; D008810:Mice, Inbred C57BL; D013026:Space Flight; D013154:Spleen / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*; D013950:Thymus Gland / Q000276:immunology*; D013997:Time Factors; D014893:Weightlessness
D016207:Cytokines