EFFECTS OF RADIATION ON SURVIVAL AND RECOVERY OF T-LYMPHOCYTE SUBSETSIN C3H HEN MICE/

Citation
Jl. Williams et al., EFFECTS OF RADIATION ON SURVIVAL AND RECOVERY OF T-LYMPHOCYTE SUBSETSIN C3H HEN MICE/, Experimental hematology, 22(6), 1994, pp. 510-516
Citations number
33
Categorie Soggetti
Medicine, Research & Experimental",Hematology
Journal title
ISSN journal
0301472X
Volume
22
Issue
6
Year of publication
1994
Pages
510 - 516
Database
ISI
SICI code
0301-472X(1994)22:6<510:EOROSA>2.0.ZU;2-E
Abstract
The aims of this study were to determine the radiosensitivities of mur ine thymic and splenic CD4(+) and CD8(+) lymphocytes and to evaluate t he regeneration of these cells in a model of radiation-induced hematop oietic and immune suppression. CD4(+) and CD8(+) cells were quantitate d using two-color flow-cytometric analysis. Cells obtained from C3H/He N mice 24 hours after exposure to 0.25-8.0 Gy (0.4 Gy/min) Co-60 were used to determine D-0 values. Thymic CD4(+) cells contained a radiosen sitive subpopulation with a D-0 of 0.97 +/- 0.05 Gy and a radioresista nt subpopulation that survived exposures up to 8.0 Gy. CD8(+) cells al so contained a radiosensitive subpopulation with a D-0 of 1.24 +/- 0.0 5 Gy and a radioresistant subpopulation with a D-0 of 3.93 +/- 2.01 Gy . Double-positive thymic CD4(+)/CD8(+) cells were uniformly radiosensi tive, with a D-0 of 1.03 +/- 0.28 Gy. Multiple T lymphocyte subpopulat ions based on radiosensitivity and CD4/CD8 antigen expression were als o observed in the spleen. When mice were exposed to a sublethal 6.5-Gy radiation dose and recovery of T lymphocyte subsets was monitored, th e relative radioresistance of CD4(+) cells resulted in a selective enr ichment of these cells among the surviving thymocytes and splenic lymp hocytes. This relative enrichment of CD4(+) cells became even more pro minent 7 days after irradiation, when atrophy of the organs was greate st. Similar, although less dramatic, effects were observed for CD8(+) cells. These studies demonstrate that (1) multiple T lymphocyte subpop ulations can be identified based on radiosensitivity and CD4/CD8 antig en expression; (2) both CD4(+) and CD8(+) cells contain radioresistant subpopulations, with the CD4(+) subpopulation being more resistant th an the CD8(+) subpopulation; and (3) although the number of radioresis tant CD4(+) cells is quite small, they persist in increased proportion s during the periods preceding and corresponding to postirradiation he matopoietic recovery.