T cell potentiation in normal and autoimmune-prone mice after extended exposure to low doses of ionizing radiation and/or caloric restriction.
In order to better understand the apparent physiologic up-regulation in response to low levels of potentially lethal insults, murine T lymphocytes were analysed for functional and phenotypic alterations after exposure to 0.005 Gy/day, 0.01 Gy/day and 0.04 Gy/day in groups of ad-libitum-fed and calorie-restricted mice. These studies were conducted in two strains of mice: the long-lived and immunologically normal C57Bl/6 +/+ and the congenic short-lived immunologically depressed C57Bl/6 lpr/lpr. Whole-body exposure to 0.01 Gy/day and 0.04 Gy/day for an extended period of 20 days was associated with an increase in splenic proliferative response and with shifts in the proportions of T cell subpopulations in the thymus and spleen of both strains. Caloric restriction independently altered functional activity and T cell subpopulations in the same direction as low dose rates of ionizing radiation. Although the dose-response augmentation in proliferative activity was similar in the two strains, observed alterations in thymic and splenic T cell subpopulations were clearly different, suggesting that different mechanisms were responsible for immune enhancement in each strain.
James
S J
SJ
Geriatric Research, Education and Clinical Center (691/W11G), V.A. Medical Center West Los Angeles. California 90073.
Makinodan
T
T
D000818:Animals; D000954:Antigens, Surface / Q000032:analysis; D001327:Autoimmune Diseases / Q000276:immunology* / Q000532:radiotherapy; D004307:Dose-Response Relationship, Radiation; D005508:Food Deprivation; D008213:Lymphocyte Activation / Q000187:drug effects; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D010835:Phytohemagglutinins / Q000494:pharmacology; D011836:Radiation Tolerance; D013154:Spleen / Q000473:pathology; D013601:T-Lymphocytes / Q000145:classification / Q000528:radiation effects*; D013950:Thymus Gland / Q000473:pathology
D000954:Antigens, Surface; D010835:Phytohemagglutinins