Increased Toll-like receptor 4 expression on T cells may be a mechanism for enhanced T cell response late after burn injury.
BACKGROUND
Burn injury is associated with a dynamic T cell response. We have previously reported an enhanced functional T cell response 14 days after burn injury. Toll-like receptors (TLR), primarily expressed on innate immune cells, have recently been identified on certain T cell subsets, including activated and memory T cells. Our hypothesis is that increased TLR4 expression on memory T cells may be a mechanism for enhanced T cell response 14 days after burn injury.


METHODS
Splenocytes from wild-type C57Bl/6 mice were harvested 14 days after a 20% total body surface area (TBSA) scald burn or sham injury. Splenocytes ex vivo were surface stained either with monoclonal anti-CD3, anti-CD4, anti-CD8, or anti-CD44 antibodies or a two-step biotin-TLR4 monoclonal antibody-streptavidin-FITC surface stain and results analyzed by flow cytometry.


RESULTS
TLR4 expression is successfully detected on CD4 and CD8 T cells. TLR4 expression is significantly (p < 0.05) increased on CD4 T cells and CD8 T cells 14 days after burn injury. There is a significant (p < 0.05) increase in CD44 (memory) CD4 and CD44 (memory) CD8 T cells 14 days after burn injury and this is associated with a significant (p < 0.05) increase of TLR4 expression in both T cell populations.


CONCLUSIONS
This study demonstrates for the first time the potential role of TLR4 expression on memory T cells generated late after burn injury. Although further analysis is required, these data reiterate the importance of adaptive immunity and the complexity of the immune response to burn injury.
Cairns
Bruce
B
Department of Surgery, Division of Trauma, Critical Care, and Burns, North Carolina Jaycee Burn Center University of North Carolina, Chapel Hill, North Carolina 27599-7228, USA. bruce.cairns@med.unc.edu
Maile
Robert
R
Barnes
Carie M
CM
Frelinger
Jeffrey A
JA
Meyer
Anthony A
AA
D000818:Animals; D002056:Burns / Q000235:genetics / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D005260:Female; D018960:Hyaluronan Receptors / Q000276:immunology; D007156:Immunologic Memory / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D013154:Spleen / Q000166:cytology / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000276:immunology* / Q000378:metabolism; D051197:Toll-Like Receptor 4 / Q000276:immunology* / Q000378:metabolism
D018960:Hyaluronan Receptors; D051197:Toll-Like Receptor 4