title: Burn injury induces an early activation response by lymph node CD4+ T cells.
abstract: Several reports have shown that burn injury primes the immune system for an early and vigorous proinflammatory CD4 T cell response, suggesting that injury might signal CD4 T cell activation. We addressed this possibility by investigating changes in CD4 T cell activation marker expression, proliferation, and T cell receptor (TCR) usage at several early time points after burn injury. Using a sensitive flow cytometry approach to measure changes in the expression of Ki-67 antigen, a nuclear protein detected only in proliferating cells, we observed an early burst of proliferation by lymph node, but not spleen, CD4 T cells 12 h after burn injury. In contrast, mice that were treated with the bacterial superantigen staphylococcal enterotoxin B (SEB) as a positive control for in vivo T cell activation did not show this early proliferation. Instead, we observed a significant increase in proliferating lymph node and spleen CD4 and CD8 T cells by 3 days after SEB treatment. Burn injury induced higher cell surface CD25 and CD152 expression on lymph node CD4 T cells, whereas SEB treatment increased CD25 and CD69 expression on CD4 and CD8 T cells. Finally, we found that burn injury induced a proliferative response at 12 h by an oligoclonal subset of TCR Vbeta-chain-expressing CD4 T cells (Vbeta4, Vbeta6, Vbeta11, and Vbeta14). Interestingly, CD4 T cells expressing the Vbeta11-TCR remained significantly increased in the lymph nodes 3 days after burn injury. Taken together, these findings indicate that burn injury induces an early proliferation and activation of CD4 T cells in the regional lymph nodes and that these proliferating cells show restricted TCR Vbeta-chain usage consistent with the idea that injury triggers an early T cell activation signal.
authors.affiliation: Department of Surgery (Immunology), Brigham and Women's Hospital and Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA.
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Purcell
authors.forename: Sinead M
authors.initials: SM
authors.lastname: Dolan
authors.forename: Sara
authors.initials: S
authors.lastname: Kriynovich
authors.forename: John A
authors.initials: JA
authors.lastname: Mannick
authors.forename: James A
authors.initials: JA
authors.lastname: Lederer
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000096:biosynthesis / Q000276:immunology; D015415:Biomarkers / Q000378:metabolism; D002056:Burns / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D049109:Cell Proliferation / Q000187:drug effects; D004768:Enterotoxins / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects / Q000276:immunology*; D008198:Lymph Nodes / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D008213:Lymphocyte Activation / Q000187:drug effects / Q000276:immunology*; D008297:Male; D051379:Mice; D015398:Signal Transduction / Q000187:drug effects / Q000276:immunology
chemical_list: D015703:Antigens, CD; D015415:Biomarkers; D004768:Enterotoxins; C031818:enterotoxin B, staphylococcal