The effect of burn injury on CD8+ and CD4+ T cells in an irradiation model of homeostatic proliferation.
BACKGROUND
Homeostatic proliferation of T cells has recently been shown to be an important mechanism in the host response to infection. However, its role in the T cell response to burn injury is unknown. In this study, we examine the effect of burn injury on CD4+ and CD8+ T cell homeostatic proliferation after irradiation.


METHODS
Wild-type C57BL/6 female mice were irradiated with six grays ionizing radiation and 48 hours later, syngeneic whole splenocytes or purified CD4+ or CD8+ T cells labeled with carboxy-fluorescein diacetate, succinimidyl ester were adoptively transferred. Two days later, mice underwent a 20% burn injury, followed by splenocyte harvest 3 and 10 days after injury.


RESULTS
Burn mice demonstrate increased splenic cellularity and CD8+ T cell proliferation after adoptive transfer of either purified CD8+ cells or whole spleen populations compared with unburned (sham) mice. In contrast, CD4+ T cell proliferation after burn injury is unchanged after adoptive transfer of whole spleen cells and drastically decreased after adoptive transfer of a purified CD4+ population compared with sham mice. Ten days after burn injury CD8+ T cells continue to demonstrate greater proliferation than CD4+ T cells.


CONCLUSIONS
CD8+ T cells are more robust than CD4+ T cells in their proliferative response after burn injury. In addition, CD8+ T cell proliferation appears less reliant on other immune cells than purified CD4+ T cell proliferation. These data reiterate the importance of CD8+ T cells in the initial immune response to burn injury.
Buchanan
Ian B
IB
North Carolina Jaycee Burn Center, Department of Surgery, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina, USA.
Maile
Robert
R
Frelinger
Jeffrey A
JA
Fair
Jeffrey H
JH
Meyer
Anthony A
AA
Cairns
Bruce A
BA
D019264:Adoptive Transfer; D000818:Animals; D001835:Body Weight; D002056:Burns / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000473:pathology / Q000528:radiation effects*; D018414:CD8-Positive T-Lymphocytes / Q000473:pathology / Q000528:radiation effects*; D049109:Cell Proliferation / Q000528:radiation effects; D004195:Disease Models, Animal; D005260:Female; D006706:Homeostasis / Q000276:immunology* / Q000528:radiation effects; D051379:Mice; D008810:Mice, Inbred C57BL; D011833:Radiation Injuries, Experimental / Q000276:immunology; D013154:Spleen / Q000166:cytology